SQL Server SELECT LAST N Rows - sql

This is a known question but the best solution I've found is something like:
SELECT TOP N *
FROM MyTable
ORDER BY Id DESC
I've a table with lots of rows. It is not a posibility to use that query because it takes lot of time. So how can I do to select last N rows without using ORDER BY?
EDIT
Sorry duplicated question of this one

You can get SQL server to select the last N rows with the following query:
select * from tbl_name order by id desc limit N;

I tested JonVD's code, but found it was very slow, 6s.
This code took 0s.
SELECT TOP(5) ORDERID, CUSTOMERID, OrderDate
FROM Orders where EmployeeID=5
Order By OrderDate DESC

You can do it by using the ROW NUMBER BY PARTITION Feature also. A great example can be found here:
I am using the Orders table of the Northwind database... Now let us retrieve the Last 5 orders placed by Employee 5:
SELECT ORDERID, CUSTOMERID, OrderDate
FROM
(
SELECT ROW_NUMBER() OVER (PARTITION BY EmployeeID ORDER BY OrderDate DESC) AS OrderedDate,*
FROM Orders
) as ordlist
WHERE ordlist.EmployeeID = 5
AND ordlist.OrderedDate <= 5

If you want to select last numbers of rows from a table.
Syntax will be like
select * from table_name except select top
(numbers of rows - how many rows you want)* from table_name
These statements work but differrent ways. thank you guys.
select * from Products except select top (77-10) * from Products
in this way you can get last 10 rows but order will show descnding way
select top 10 * from products
order by productId desc
select * from products
where productid in (select top 10 productID from products)
order by productID desc
select * from products where productID not in
(select top((select COUNT(*) from products ) -10 )productID from products)

First you most get record count from
Declare #TableRowsCount Int
select #TableRowsCount= COUNT(*) from <Your_Table>
And then :
In SQL Server 2012
SELECT *
FROM <Your_Table> As L
ORDER BY L.<your Field>
OFFSET <#TableRowsCount-#N> ROWS
FETCH NEXT #N ROWS ONLY;
In SQL Server 2008
SELECT *
FROM
(
SELECT ROW_NUMBER() OVER(ORDER BY ID) AS sequencenumber, *
FROM <Your_Table>
Order By <your Field>
) AS TempTable
WHERE sequencenumber > #TableRowsCount-#N

In a very general way and to support SQL server here is
SELECT TOP(N) *
FROM tbl_name
ORDER BY tbl_id DESC
and for the performance, it is not bad (less than one second for more than 10,000 records On Server machine)

Is "Id" indexed? If not, that's an important thing to do (I suspect it is already indexed).
Also, do you need to return ALL columns? You may be able to get a substantial improvement in speed if you only actually need a smaller subset of columns which can be FULLY catered for by the index on the ID column - e.g. if you have a NONCLUSTERED index on the Id column, with no other fields included in the index, then it would have to do a lookup on the clustered index to actually get the rest of the columns to return and that could be making up a lot of the cost of the query. If it's a CLUSTERED index, or a NONCLUSTERED index that includes all the other fields you want to return in the query, then you should be fine.

select * from (select top 6 * from vwTable order by Hours desc) T order by Hours

Here's something you can try without an order by but I think it requires that each row is unique. N is the number of rows you want, L is the number of rows in the table.
select * from tbl_name except select top L-N * from tbl_name
As noted before, which rows are returned is undefined.
EDIT: this is actually dog slow. Of no value really.

A technique I use to query the MOST RECENT rows in very large tables (100+ million or 1+ billion rows) is limiting the query to "reading" only the most recent "N" percentage of RECENT ROWS. This is real world applications, for example I do this for non-historic Recent Weather Data, or recent News feed searches or Recent GPS location data point data.
This is a huge performance improvement if you know for certain that your rows are in the most recent TOP 5% of the table for example. Such that even if there are indexes on the Tables, it further limits the possibilites to only 5% of rows in tables which have 100+ million or 1+ billion rows. This is especially the case when Older Data will require Physical Disk reads and not only Logical In Memory reads.
This is well more efficient than SELECT TOP | PERCENT | LIMIT as it does not select the rows, but merely limit the portion of the data to be searched.
DECLARE #RowIdTableA BIGINT
DECLARE #RowIdTableB BIGINT
DECLARE #TopPercent FLOAT
-- Given that there is an Sequential Identity Column
-- Limit query to only rows in the most recent TOP 5% of rows
SET #TopPercent = .05
SELECT #RowIdTableA = (MAX(TableAId) - (MAX(TableAId) * #TopPercent)) FROM TableA
SELECT #RowIdTableB = (MAX(TableBId) - (MAX(TableBId) * #TopPercent)) FROM TableB
SELECT *
FROM TableA a
INNER JOIN TableB b ON a.KeyId = b.KeyId
WHERE a.Id > #RowIdTableA AND b.Id > #RowIdTableB AND
a.SomeOtherCriteria = 'Whatever'

MS doesn't support LIMIT in t-sql. Most of the times i just get MAX(ID) and then subtract.
select * from ORDERS where ID >(select MAX(ID)-10 from ORDERS)
This will return less than 10 records when ID is not sequential.

This query returns last N rows in correct order, but it's performance is poor
select *
from (
select top N *
from TableName t
order by t.[Id] desc
) as temp
order by temp.[Id]

use desc with orderby at the end of the query to get the last values.

This may not be quite the right fit to the question, but…
OFFSET clause
The OFFSET number clause enables you to skip over a number of rows and then return rows after that.
That doc link is to Postgres; I don't know if this applies to Sybase/MS SQL Server.

DECLARE #MYVAR NVARCHAR(100)
DECLARE #step int
SET #step = 0;
DECLARE MYTESTCURSOR CURSOR
DYNAMIC
FOR
SELECT col FROM [dbo].[table]
OPEN MYTESTCURSOR
FETCH LAST FROM MYTESTCURSOR INTO #MYVAR
print #MYVAR;
WHILE #step < 10
BEGIN
FETCH PRIOR FROM MYTESTCURSOR INTO #MYVAR
print #MYVAR;
SET #step = #step + 1;
END
CLOSE MYTESTCURSOR
DEALLOCATE MYTESTCURSOR

In order to get the result in ascending order
SELECT n.*
FROM
(
SELECT *
FROM MyTable
ORDER BY id DESC
LIMIT N
) n
ORDER BY n.id ASC

I stumpled acros this issue while using SQL server
What i did to resolve it is order the results descending and giving row number to the results of that, After i filtered the results and turned them around again.
SELECT *
FROM (
SELECT *
,[rn] = ROW_NUMBER() OVER (ORDER BY [column] DESC)
FROM [table]
) A
WHERE A.[rn] < 3
ORDER BY [column] ASC
Easy copy paste answer

To display last 3 rows without using order by:
select * from Lms_Books_Details where Book_Code not in
(select top((select COUNT(*) from Lms_Books_Details ) -3 ) book_code from Lms_Books_Details)

Try using the EXCEPT syntax.
Something like this:
SELECT *
FROM clientDetails
EXCEPT
(SELECT TOP (numbers of rows - how many rows you want) *
FROM clientDetails)

Related

Select nth row using where condition in oracle database [duplicate]

I'm interested in learning some (ideally) database agnostic ways of selecting the nth row from a database table. It would also be interesting to see how this can be achieved using the native functionality of the following databases:
SQL Server
MySQL
PostgreSQL
SQLite
Oracle
I am currently doing something like the following in SQL Server 2005, but I'd be interested in seeing other's more agnostic approaches:
WITH Ordered AS (
SELECT ROW_NUMBER() OVER (ORDER BY OrderID) AS RowNumber, OrderID, OrderDate
FROM Orders)
SELECT *
FROM Ordered
WHERE RowNumber = 1000000
Credit for the above SQL: Firoz Ansari's Weblog
Update: See Troels Arvin's answer regarding the SQL standard. Troels, have you got any links we can cite?
There are ways of doing this in optional parts of the standard, but a lot of databases support their own way of doing it.
A really good site that talks about this and other things is http://troels.arvin.dk/db/rdbms/#select-limit.
Basically, PostgreSQL and MySQL supports the non-standard:
SELECT...
LIMIT y OFFSET x
Oracle, DB2 and MSSQL supports the standard windowing functions:
SELECT * FROM (
SELECT
ROW_NUMBER() OVER (ORDER BY key ASC) AS rownumber,
columns
FROM tablename
) AS foo
WHERE rownumber <= n
(which I just copied from the site linked above since I never use those DBs)
Update: As of PostgreSQL 8.4 the standard windowing functions are supported, so expect the second example to work for PostgreSQL as well.
Update: SQLite added window functions support in version 3.25.0 on 2018-09-15 so both forms also work in SQLite.
PostgreSQL supports windowing functions as defined by the SQL standard, but they're awkward, so most people use (the non-standard) LIMIT / OFFSET:
SELECT
*
FROM
mytable
ORDER BY
somefield
LIMIT 1 OFFSET 20;
This example selects the 21st row. OFFSET 20 is telling Postgres to skip the first 20 records. If you don't specify an ORDER BY clause, there's no guarantee which record you will get back, which is rarely useful.
I'm not sure about any of the rest, but I know SQLite and MySQL don't have any "default" row ordering. In those two dialects, at least, the following snippet grabs the 15th entry from the_table, sorting by the date/time it was added:
SELECT *
FROM the_table
ORDER BY added DESC
LIMIT 1,15
(of course, you'd need to have an added DATETIME field, and set it to the date/time that entry was added...)
SQL 2005 and above has this feature built-in. Use the ROW_NUMBER() function. It is excellent for web-pages with a << Prev and Next >> style browsing:
Syntax:
SELECT
*
FROM
(
SELECT
ROW_NUMBER () OVER (ORDER BY MyColumnToOrderBy) AS RowNum,
*
FROM
Table_1
) sub
WHERE
RowNum = 23
I suspect this is wildly inefficient but is quite a simple approach, which worked on a small dataset that I tried it on.
select top 1 field
from table
where field in (select top 5 field from table order by field asc)
order by field desc
This would get the 5th item, change the second top number to get a different nth item
SQL server only (I think) but should work on older versions that do not support ROW_NUMBER().
Verify it on SQL Server:
Select top 10 * From emp
EXCEPT
Select top 9 * From emp
This will give you 10th ROW of emp table!
Contrary to what some of the answers claim, the SQL standard is not silent regarding this subject.
Since SQL:2003, you have been able to use "window functions" to skip rows and limit result sets.
And in SQL:2008, a slightly simpler approach had been added, using
OFFSET skip ROWS
FETCH FIRST n ROWS ONLY
Personally, I don't think that SQL:2008's addition was really needed, so if I were ISO, I would have kept it out of an already rather large standard.
1 small change: n-1 instead of n.
select *
from thetable
limit n-1, 1
SQL SERVER
Select n' th record from top
SELECT * FROM (
SELECT
ID, NAME, ROW_NUMBER() OVER(ORDER BY ID) AS ROW
FROM TABLE
) AS TMP
WHERE ROW = n
select n' th record from bottom
SELECT * FROM (
SELECT
ID, NAME, ROW_NUMBER() OVER(ORDER BY ID DESC) AS ROW
FROM TABLE
) AS TMP
WHERE ROW = n
When we used to work in MSSQL 2000, we did what we called the "triple-flip":
EDITED
DECLARE #InnerPageSize int
DECLARE #OuterPageSize int
DECLARE #Count int
SELECT #Count = COUNT(<column>) FROM <TABLE>
SET #InnerPageSize = #PageNum * #PageSize
SET #OuterPageSize = #Count - ((#PageNum - 1) * #PageSize)
IF (#OuterPageSize < 0)
SET #OuterPageSize = 0
ELSE IF (#OuterPageSize > #PageSize)
SET #OuterPageSize = #PageSize
DECLARE #sql NVARCHAR(8000)
SET #sql = 'SELECT * FROM
(
SELECT TOP ' + CAST(#OuterPageSize AS nvarchar(5)) + ' * FROM
(
SELECT TOP ' + CAST(#InnerPageSize AS nvarchar(5)) + ' * FROM <TABLE> ORDER BY <column> ASC
) AS t1 ORDER BY <column> DESC
) AS t2 ORDER BY <column> ASC'
PRINT #sql
EXECUTE sp_executesql #sql
It wasn't elegant, and it wasn't fast, but it worked.
In Oracle 12c, You may use OFFSET..FETCH..ROWS option with ORDER BY
For example, to get the 3rd record from top:
SELECT *
FROM sometable
ORDER BY column_name
OFFSET 2 ROWS FETCH NEXT 1 ROWS ONLY;
Here is a fast solution of your confusion.
SELECT * FROM table ORDER BY `id` DESC LIMIT N, 1
Here You may get Last row by Filling N=0, Second last by N=1, Fourth Last By Filling N=3 and so on.
This is very common question over the interview and this is Very simple ans of it.
Further If you want Amount, ID or some Numeric Sorting Order than u may go for CAST function in MySQL.
SELECT DISTINCT (`amount`)
FROM cart
ORDER BY CAST( `amount` AS SIGNED ) DESC
LIMIT 4 , 1
Here By filling N = 4 You will be able to get Fifth Last Record of Highest Amount from CART table. You can fit your field and table name and come up with solution.
ADD:
LIMIT n,1
That will limit the results to one result starting at result n.
Oracle:
select * from (select foo from bar order by foo) where ROWNUM = x
For example, if you want to select every 10th row in MSSQL, you can use;
SELECT * FROM (
SELECT
ROW_NUMBER() OVER (ORDER BY ColumnName1 ASC) AS rownumber, ColumnName1, ColumnName2
FROM TableName
) AS foo
WHERE rownumber % 10 = 0
Just take the MOD and change number 10 here any number you want.
For SQL Server, a generic way to go by row number is as such:
SET ROWCOUNT #row --#row = the row number you wish to work on.
For Example:
set rowcount 20 --sets row to 20th row
select meat, cheese from dbo.sandwich --select columns from table at 20th row
set rowcount 0 --sets rowcount back to all rows
This will return the 20th row's information. Be sure to put in the rowcount 0 afterward.
Here's a generic version of a sproc I recently wrote for Oracle that allows for dynamic paging/sorting - HTH
-- p_LowerBound = first row # in the returned set; if second page of 10 rows,
-- this would be 11 (-1 for unbounded/not set)
-- p_UpperBound = last row # in the returned set; if second page of 10 rows,
-- this would be 20 (-1 for unbounded/not set)
OPEN o_Cursor FOR
SELECT * FROM (
SELECT
Column1,
Column2
rownum AS rn
FROM
(
SELECT
tbl.Column1,
tbl.column2
FROM MyTable tbl
WHERE
tbl.Column1 = p_PKParam OR
tbl.Column1 = -1
ORDER BY
DECODE(p_sortOrder, 'A', DECODE(p_sortColumn, 1, Column1, 'X'),'X'),
DECODE(p_sortOrder, 'D', DECODE(p_sortColumn, 1, Column1, 'X'),'X') DESC,
DECODE(p_sortOrder, 'A', DECODE(p_sortColumn, 2, Column2, sysdate),sysdate),
DECODE(p_sortOrder, 'D', DECODE(p_sortColumn, 2, Column2, sysdate),sysdate) DESC
))
WHERE
(rn >= p_lowerBound OR p_lowerBound = -1) AND
(rn <= p_upperBound OR p_upperBound = -1);
But really, isn't all this really just parlor tricks for good database design in the first place? The few times I needed functionality like this it was for a simple one off query to make a quick report. For any real work, using tricks like these is inviting trouble. If selecting a particular row is needed then just have a column with a sequential value and be done with it.
Nothing fancy, no special functions, in case you use Caché like I do...
SELECT TOP 1 * FROM (
SELECT TOP n * FROM <table>
ORDER BY ID Desc
)
ORDER BY ID ASC
Given that you have an ID column or a datestamp column you can trust.
For SQL server, the following will return the first row from giving table.
declare #rowNumber int = 1;
select TOP(#rowNumber) * from [dbo].[someTable];
EXCEPT
select TOP(#rowNumber - 1) * from [dbo].[someTable];
You can loop through the values with something like this:
WHILE #constVar > 0
BEGIN
declare #rowNumber int = #consVar;
select TOP(#rowNumber) * from [dbo].[someTable];
EXCEPT
select TOP(#rowNumber - 1) * from [dbo].[someTable];
SET #constVar = #constVar - 1;
END;
LIMIT n,1 doesn't work in MS SQL Server. I think it's just about the only major database that doesn't support that syntax. To be fair, it isn't part of the SQL standard, although it is so widely supported that it should be. In everything except SQL server LIMIT works great. For SQL server, I haven't been able to find an elegant solution.
In Sybase SQL Anywhere:
SELECT TOP 1 START AT n * from table ORDER BY whatever
Don't forget the ORDER BY or it's meaningless.
T-SQL - Selecting N'th RecordNumber from a Table
select * from
(select row_number() over (order by Rand() desc) as Rno,* from TableName) T where T.Rno = RecordNumber
Where RecordNumber --> Record Number to Select
TableName --> To be Replaced with your Table Name
For e.g. to select 5 th record from a table Employee, your query should be
select * from
(select row_number() over (order by Rand() desc) as Rno,* from Employee) T where T.Rno = 5
SELECT
top 1 *
FROM
table_name
WHERE
column_name IN (
SELECT
top N column_name
FROM
TABLE
ORDER BY
column_name
)
ORDER BY
column_name DESC
I've written this query for finding Nth row.
Example with this query would be
SELECT
top 1 *
FROM
Employee
WHERE
emp_id IN (
SELECT
top 7 emp_id
FROM
Employee
ORDER BY
emp_id
)
ORDER BY
emp_id DESC
I'm a bit late to the party here but I have done this without the need for windowing or using
WHERE x IN (...)
SELECT TOP 1
--select the value needed from t1
[col2]
FROM
(
SELECT TOP 2 --the Nth row, alter this to taste
UE2.[col1],
UE2.[col2],
UE2.[date],
UE2.[time],
UE2.[UID]
FROM
[table1] AS UE2
WHERE
UE2.[col1] = ID --this is a subquery
AND
UE2.[col2] IS NOT NULL
ORDER BY
UE2.[date] DESC, UE2.[time] DESC --sorting by date and time newest first
) AS t1
ORDER BY t1.[date] ASC, t1.[time] ASC --this reverses the order of the sort in t1
It seems to work fairly fast although to be fair I only have around 500 rows of data
This works in MSSQL
SELECT * FROM emp a
WHERE n = (
SELECT COUNT( _rowid)
FROM emp b
WHERE a. _rowid >= b. _rowid
);
unbelievable that you can find a SQL engine executing this one ...
WITH sentence AS
(SELECT
stuff,
row = ROW_NUMBER() OVER (ORDER BY Id)
FROM
SentenceType
)
SELECT
sen.stuff
FROM sentence sen
WHERE sen.row = (ABS(CHECKSUM(NEWID())) % 100) + 1
select * from
(select * from ordered order by order_id limit 100) x order by
x.order_id desc limit 1;
First select top 100 rows by ordering in ascending and then select last row by ordering in descending and limit to 1. However this is a very expensive statement as it access the data twice.
It seems to me that, to be efficient, you need to 1) generate a random number between 0 and one less than the number of database records, and 2) be able to select the row at that position. Unfortunately, different databases have different random number generators and different ways to select a row at a position in a result set - usually you specify how many rows to skip and how many rows you want, but it's done differently for different databases. Here is something that works for me in SQLite:
select *
from Table
limit abs(random()) % (select count(*) from Words), 1;
It does depend on being able to use a subquery in the limit clause (which in SQLite is LIMIT <recs to skip>,<recs to take>) Selecting the number of records in a table should be particularly efficient, being part of the database's meta data, but that depends on the database's implementation. Also, I don't know if the query will actually build the result set before retrieving the Nth record, but I would hope that it doesn't need to. Note that I'm not specifying an "order by" clause. It might be better to "order by" something like the primary key, which will have an index - getting the Nth record from an index might be faster if the database can't get the Nth record from the database itself without building the result set.
Most suitable answer I have seen on this article for sql server
WITH myTableWithRows AS (
SELECT (ROW_NUMBER() OVER (ORDER BY myTable.SomeField)) as row,*
FROM myTable)
SELECT * FROM myTableWithRows WHERE row = 3

SQL query to fetch second last row or nth row from the table [duplicate]

I'm interested in learning some (ideally) database agnostic ways of selecting the nth row from a database table. It would also be interesting to see how this can be achieved using the native functionality of the following databases:
SQL Server
MySQL
PostgreSQL
SQLite
Oracle
I am currently doing something like the following in SQL Server 2005, but I'd be interested in seeing other's more agnostic approaches:
WITH Ordered AS (
SELECT ROW_NUMBER() OVER (ORDER BY OrderID) AS RowNumber, OrderID, OrderDate
FROM Orders)
SELECT *
FROM Ordered
WHERE RowNumber = 1000000
Credit for the above SQL: Firoz Ansari's Weblog
Update: See Troels Arvin's answer regarding the SQL standard. Troels, have you got any links we can cite?
There are ways of doing this in optional parts of the standard, but a lot of databases support their own way of doing it.
A really good site that talks about this and other things is http://troels.arvin.dk/db/rdbms/#select-limit.
Basically, PostgreSQL and MySQL supports the non-standard:
SELECT...
LIMIT y OFFSET x
Oracle, DB2 and MSSQL supports the standard windowing functions:
SELECT * FROM (
SELECT
ROW_NUMBER() OVER (ORDER BY key ASC) AS rownumber,
columns
FROM tablename
) AS foo
WHERE rownumber <= n
(which I just copied from the site linked above since I never use those DBs)
Update: As of PostgreSQL 8.4 the standard windowing functions are supported, so expect the second example to work for PostgreSQL as well.
Update: SQLite added window functions support in version 3.25.0 on 2018-09-15 so both forms also work in SQLite.
PostgreSQL supports windowing functions as defined by the SQL standard, but they're awkward, so most people use (the non-standard) LIMIT / OFFSET:
SELECT
*
FROM
mytable
ORDER BY
somefield
LIMIT 1 OFFSET 20;
This example selects the 21st row. OFFSET 20 is telling Postgres to skip the first 20 records. If you don't specify an ORDER BY clause, there's no guarantee which record you will get back, which is rarely useful.
I'm not sure about any of the rest, but I know SQLite and MySQL don't have any "default" row ordering. In those two dialects, at least, the following snippet grabs the 15th entry from the_table, sorting by the date/time it was added:
SELECT *
FROM the_table
ORDER BY added DESC
LIMIT 1,15
(of course, you'd need to have an added DATETIME field, and set it to the date/time that entry was added...)
SQL 2005 and above has this feature built-in. Use the ROW_NUMBER() function. It is excellent for web-pages with a << Prev and Next >> style browsing:
Syntax:
SELECT
*
FROM
(
SELECT
ROW_NUMBER () OVER (ORDER BY MyColumnToOrderBy) AS RowNum,
*
FROM
Table_1
) sub
WHERE
RowNum = 23
I suspect this is wildly inefficient but is quite a simple approach, which worked on a small dataset that I tried it on.
select top 1 field
from table
where field in (select top 5 field from table order by field asc)
order by field desc
This would get the 5th item, change the second top number to get a different nth item
SQL server only (I think) but should work on older versions that do not support ROW_NUMBER().
Verify it on SQL Server:
Select top 10 * From emp
EXCEPT
Select top 9 * From emp
This will give you 10th ROW of emp table!
Contrary to what some of the answers claim, the SQL standard is not silent regarding this subject.
Since SQL:2003, you have been able to use "window functions" to skip rows and limit result sets.
And in SQL:2008, a slightly simpler approach had been added, using
OFFSET skip ROWS
FETCH FIRST n ROWS ONLY
Personally, I don't think that SQL:2008's addition was really needed, so if I were ISO, I would have kept it out of an already rather large standard.
1 small change: n-1 instead of n.
select *
from thetable
limit n-1, 1
SQL SERVER
Select n' th record from top
SELECT * FROM (
SELECT
ID, NAME, ROW_NUMBER() OVER(ORDER BY ID) AS ROW
FROM TABLE
) AS TMP
WHERE ROW = n
select n' th record from bottom
SELECT * FROM (
SELECT
ID, NAME, ROW_NUMBER() OVER(ORDER BY ID DESC) AS ROW
FROM TABLE
) AS TMP
WHERE ROW = n
When we used to work in MSSQL 2000, we did what we called the "triple-flip":
EDITED
DECLARE #InnerPageSize int
DECLARE #OuterPageSize int
DECLARE #Count int
SELECT #Count = COUNT(<column>) FROM <TABLE>
SET #InnerPageSize = #PageNum * #PageSize
SET #OuterPageSize = #Count - ((#PageNum - 1) * #PageSize)
IF (#OuterPageSize < 0)
SET #OuterPageSize = 0
ELSE IF (#OuterPageSize > #PageSize)
SET #OuterPageSize = #PageSize
DECLARE #sql NVARCHAR(8000)
SET #sql = 'SELECT * FROM
(
SELECT TOP ' + CAST(#OuterPageSize AS nvarchar(5)) + ' * FROM
(
SELECT TOP ' + CAST(#InnerPageSize AS nvarchar(5)) + ' * FROM <TABLE> ORDER BY <column> ASC
) AS t1 ORDER BY <column> DESC
) AS t2 ORDER BY <column> ASC'
PRINT #sql
EXECUTE sp_executesql #sql
It wasn't elegant, and it wasn't fast, but it worked.
In Oracle 12c, You may use OFFSET..FETCH..ROWS option with ORDER BY
For example, to get the 3rd record from top:
SELECT *
FROM sometable
ORDER BY column_name
OFFSET 2 ROWS FETCH NEXT 1 ROWS ONLY;
Here is a fast solution of your confusion.
SELECT * FROM table ORDER BY `id` DESC LIMIT N, 1
Here You may get Last row by Filling N=0, Second last by N=1, Fourth Last By Filling N=3 and so on.
This is very common question over the interview and this is Very simple ans of it.
Further If you want Amount, ID or some Numeric Sorting Order than u may go for CAST function in MySQL.
SELECT DISTINCT (`amount`)
FROM cart
ORDER BY CAST( `amount` AS SIGNED ) DESC
LIMIT 4 , 1
Here By filling N = 4 You will be able to get Fifth Last Record of Highest Amount from CART table. You can fit your field and table name and come up with solution.
ADD:
LIMIT n,1
That will limit the results to one result starting at result n.
Oracle:
select * from (select foo from bar order by foo) where ROWNUM = x
For example, if you want to select every 10th row in MSSQL, you can use;
SELECT * FROM (
SELECT
ROW_NUMBER() OVER (ORDER BY ColumnName1 ASC) AS rownumber, ColumnName1, ColumnName2
FROM TableName
) AS foo
WHERE rownumber % 10 = 0
Just take the MOD and change number 10 here any number you want.
For SQL Server, a generic way to go by row number is as such:
SET ROWCOUNT #row --#row = the row number you wish to work on.
For Example:
set rowcount 20 --sets row to 20th row
select meat, cheese from dbo.sandwich --select columns from table at 20th row
set rowcount 0 --sets rowcount back to all rows
This will return the 20th row's information. Be sure to put in the rowcount 0 afterward.
Here's a generic version of a sproc I recently wrote for Oracle that allows for dynamic paging/sorting - HTH
-- p_LowerBound = first row # in the returned set; if second page of 10 rows,
-- this would be 11 (-1 for unbounded/not set)
-- p_UpperBound = last row # in the returned set; if second page of 10 rows,
-- this would be 20 (-1 for unbounded/not set)
OPEN o_Cursor FOR
SELECT * FROM (
SELECT
Column1,
Column2
rownum AS rn
FROM
(
SELECT
tbl.Column1,
tbl.column2
FROM MyTable tbl
WHERE
tbl.Column1 = p_PKParam OR
tbl.Column1 = -1
ORDER BY
DECODE(p_sortOrder, 'A', DECODE(p_sortColumn, 1, Column1, 'X'),'X'),
DECODE(p_sortOrder, 'D', DECODE(p_sortColumn, 1, Column1, 'X'),'X') DESC,
DECODE(p_sortOrder, 'A', DECODE(p_sortColumn, 2, Column2, sysdate),sysdate),
DECODE(p_sortOrder, 'D', DECODE(p_sortColumn, 2, Column2, sysdate),sysdate) DESC
))
WHERE
(rn >= p_lowerBound OR p_lowerBound = -1) AND
(rn <= p_upperBound OR p_upperBound = -1);
But really, isn't all this really just parlor tricks for good database design in the first place? The few times I needed functionality like this it was for a simple one off query to make a quick report. For any real work, using tricks like these is inviting trouble. If selecting a particular row is needed then just have a column with a sequential value and be done with it.
Nothing fancy, no special functions, in case you use Caché like I do...
SELECT TOP 1 * FROM (
SELECT TOP n * FROM <table>
ORDER BY ID Desc
)
ORDER BY ID ASC
Given that you have an ID column or a datestamp column you can trust.
For SQL server, the following will return the first row from giving table.
declare #rowNumber int = 1;
select TOP(#rowNumber) * from [dbo].[someTable];
EXCEPT
select TOP(#rowNumber - 1) * from [dbo].[someTable];
You can loop through the values with something like this:
WHILE #constVar > 0
BEGIN
declare #rowNumber int = #consVar;
select TOP(#rowNumber) * from [dbo].[someTable];
EXCEPT
select TOP(#rowNumber - 1) * from [dbo].[someTable];
SET #constVar = #constVar - 1;
END;
LIMIT n,1 doesn't work in MS SQL Server. I think it's just about the only major database that doesn't support that syntax. To be fair, it isn't part of the SQL standard, although it is so widely supported that it should be. In everything except SQL server LIMIT works great. For SQL server, I haven't been able to find an elegant solution.
In Sybase SQL Anywhere:
SELECT TOP 1 START AT n * from table ORDER BY whatever
Don't forget the ORDER BY or it's meaningless.
T-SQL - Selecting N'th RecordNumber from a Table
select * from
(select row_number() over (order by Rand() desc) as Rno,* from TableName) T where T.Rno = RecordNumber
Where RecordNumber --> Record Number to Select
TableName --> To be Replaced with your Table Name
For e.g. to select 5 th record from a table Employee, your query should be
select * from
(select row_number() over (order by Rand() desc) as Rno,* from Employee) T where T.Rno = 5
SELECT
top 1 *
FROM
table_name
WHERE
column_name IN (
SELECT
top N column_name
FROM
TABLE
ORDER BY
column_name
)
ORDER BY
column_name DESC
I've written this query for finding Nth row.
Example with this query would be
SELECT
top 1 *
FROM
Employee
WHERE
emp_id IN (
SELECT
top 7 emp_id
FROM
Employee
ORDER BY
emp_id
)
ORDER BY
emp_id DESC
I'm a bit late to the party here but I have done this without the need for windowing or using
WHERE x IN (...)
SELECT TOP 1
--select the value needed from t1
[col2]
FROM
(
SELECT TOP 2 --the Nth row, alter this to taste
UE2.[col1],
UE2.[col2],
UE2.[date],
UE2.[time],
UE2.[UID]
FROM
[table1] AS UE2
WHERE
UE2.[col1] = ID --this is a subquery
AND
UE2.[col2] IS NOT NULL
ORDER BY
UE2.[date] DESC, UE2.[time] DESC --sorting by date and time newest first
) AS t1
ORDER BY t1.[date] ASC, t1.[time] ASC --this reverses the order of the sort in t1
It seems to work fairly fast although to be fair I only have around 500 rows of data
This works in MSSQL
SELECT * FROM emp a
WHERE n = (
SELECT COUNT( _rowid)
FROM emp b
WHERE a. _rowid >= b. _rowid
);
unbelievable that you can find a SQL engine executing this one ...
WITH sentence AS
(SELECT
stuff,
row = ROW_NUMBER() OVER (ORDER BY Id)
FROM
SentenceType
)
SELECT
sen.stuff
FROM sentence sen
WHERE sen.row = (ABS(CHECKSUM(NEWID())) % 100) + 1
select * from
(select * from ordered order by order_id limit 100) x order by
x.order_id desc limit 1;
First select top 100 rows by ordering in ascending and then select last row by ordering in descending and limit to 1. However this is a very expensive statement as it access the data twice.
It seems to me that, to be efficient, you need to 1) generate a random number between 0 and one less than the number of database records, and 2) be able to select the row at that position. Unfortunately, different databases have different random number generators and different ways to select a row at a position in a result set - usually you specify how many rows to skip and how many rows you want, but it's done differently for different databases. Here is something that works for me in SQLite:
select *
from Table
limit abs(random()) % (select count(*) from Words), 1;
It does depend on being able to use a subquery in the limit clause (which in SQLite is LIMIT <recs to skip>,<recs to take>) Selecting the number of records in a table should be particularly efficient, being part of the database's meta data, but that depends on the database's implementation. Also, I don't know if the query will actually build the result set before retrieving the Nth record, but I would hope that it doesn't need to. Note that I'm not specifying an "order by" clause. It might be better to "order by" something like the primary key, which will have an index - getting the Nth record from an index might be faster if the database can't get the Nth record from the database itself without building the result set.
Most suitable answer I have seen on this article for sql server
WITH myTableWithRows AS (
SELECT (ROW_NUMBER() OVER (ORDER BY myTable.SomeField)) as row,*
FROM myTable)
SELECT * FROM myTableWithRows WHERE row = 3

Get total row count while paging

I have a search screen where the user has 5 filters to search on.
I constructed a dynamic query, based on these filter values, and page 10 results at a time.
This is working fine in SQL2012 using OFFSET and FETCH, but I'm using two queries to do this.
I want to show the 10 results and display the total number of rows found by the query (let's say 1000).
Currently I do this by running the query twice - once for the Total count, then again to page the 10 rows.
Is there a more efficient way to do this?
You don't have to run the query twice.
SELECT ..., total_count = COUNT(*) OVER()
FROM ...
ORDER BY ...
OFFSET 120 ROWS
FETCH NEXT 10 ROWS ONLY;
Based on the chat, it seems your problem is a little more complex - you are applying DISTINCT to the result in addition to paging. This can make it complex to determine exactly what the COUNT() should look like and where it should go. Here is one way (I just want to demonstrate this rather than try to incorporate the technique into your much more complex query from chat):
USE tempdb;
GO
CREATE TABLE dbo.PagingSample(id INT,name SYSNAME);
-- insert 20 rows, 10 x 2 duplicates
INSERT dbo.PagingSample SELECT TOP (10) [object_id], name FROM sys.all_columns;
INSERT dbo.PagingSample SELECT TOP (10) [object_id], name FROM sys.all_columns;
SELECT COUNT(*) FROM dbo.PagingSample; -- 20
SELECT COUNT(*) FROM (SELECT DISTINCT id, name FROM dbo.PagingSample) AS x; -- 10
SELECT DISTINCT id, name FROM dbo.PagingSample; -- 10 rows
SELECT DISTINCT id, name, COUNT(*) OVER() -- 20 (DISTINCT is not computed yet)
FROM dbo.PagingSample
ORDER BY id, name
OFFSET (0) ROWS FETCH NEXT (5) ROWS ONLY; -- 5 rows
-- this returns 5 rows but shows the pre- and post-distinct counts:
SELECT PostDistinctCount = COUNT(*) OVER() -- 10,
PreDistinctCount -- 20,
id, name
FROM
(
SELECT DISTINCT id, name, PreDistinctCount = COUNT(*) OVER()
FROM dbo.PagingSample
-- INNER JOIN ...
) AS x
ORDER BY id, name
OFFSET (0) ROWS FETCH NEXT (5) ROWS ONLY;
Clean up:
DROP TABLE dbo.PagingSample;
GO
My solution is similar to "rs. answer"
DECLARE #PageNumber AS INT, #RowspPage AS INT
SET #PageNumber = 2
SET #RowspPage = 5
SELECT COUNT(*) OVER() totalrow_count,*
FROM databasename
where columnname like '%abc%'
ORDER BY columnname
OFFSET ((#PageNumber - 1) * #RowspPage) ROWS
FETCH NEXT #RowspPage ROWS ONLY;
The return result will include totalrow_count as the first column name
Can you try something like this
SELECT TOP 10 * FROM
(
SELECT COUNT(*) OVER() TOTALCNT, T.*
FROM TABLE1 T
WHERE col1 = 'somefilter'
) v
or
SELECT * FROM
(
SELECT COUNT(*) OVER() TOTALCNT, T.*
FROM TABLE1 T
WHERE col1 = 'somefilter'
) v
ORDER BY COL1
OFFSET 0 ROWS FETCH FIRST 10 ROWS ONLY
Now you have total count in your totalcnt column and you can use this column to show total number of rows
In my testing with a complex join and ~6,000 records returned, it's much faster to do two separate queries. Faster, as in milliseconds total to get the total and separately bring back a subset of 100 records, vs 17 seconds to do the combined query. Anyone else see this kind of performance hit? Obviously, it could have something to do with the data structure but this is still a huge difference.
I hope I'm not too late to jump in on this question, but I ran across a very similar problem tonight. I had a paging class that was over inflating the number of results returned because the previous developer was dropping the DISTINCT and just doing a SELECT count(*) of the table joins. While this doesn't solve the 2 query problem I ended up using a nested query so that it looked like this:
Original Query
SELECT DISTINCT
field1, field2
FROM
table1 t1
left join table2 t2 on t2.id = t1.id
Over Inflated Results Query
SELECT
count(*)
FROM
table1 t1
left join table2 t2 on t2.id = t1.id
My Results Query Solution
SELECT
count(*)
FROM
(SELECT DISTINCT
field1, field2
FROM
table1 t1
left join table2 t2 on t2.id = t1.id) as tbl;

Selecting Nth Record in an SQL Query

I have an SQL Query that i'm running but I only want to select a specific row. For example lets say my query was:
Select * from Comments
Lets say this returns 10 rows, I only want to select the 8th record returned by this query. I know I can do:
Select Top 5 * from Comments
To get the top 5 records of that query but I only want to select a certain record, is there anything I can put into this query to do that (similar to top).
Thanks
jack
This is a classic interview question.
In Ms SQL 2005+ you can use the ROW_NUMBER() keyword and have the Predicate ROW_NUMBER = n
USE AdventureWorks;
GO
WITH OrderedOrders AS
(
SELECT SalesOrderID, OrderDate,
ROW_NUMBER() OVER (ORDER BY OrderDate) AS 'RowNumber'
FROM Sales.SalesOrderHeader
)
SELECT *
FROM OrderedOrders
WHERE RowNumber = 5;
In SQL2000 you could do something like
SELECT Top 1 *FROM
[tblApplications]
where [ApplicationID] In
(
SELECT TOP 5 [ApplicationID]
FROM [dbo].[tblApplications]
order by applicationId Desc
)
How about
SELECT TOP 1 * FROM
(SELECT TOP 8 * FROM Comments ORDER BY foo ASC)
ORDER BY foo DESC
First, you should say which RDBMS you're using.
Second, you should give careful thought to what it is you're trying to accomplish. Relational Databases are set-based. In general, the order of elements in a set does not matter. You'll want to ask why it matters in this case, then see if there's a better way to embed the concept of order into the query itself.
For instance, in SQL Server 2005 (and other RDBMS), you can use the ROW_NUMBER function to assign a sequential number to each row returned, based on the criteria you specify. You could then select rows based on the row number. Example from Books Online:
USE AdventureWorks;
GO
WITH OrderedOrders AS
(
SELECT SalesOrderID, OrderDate,
ROW_NUMBER() OVER (ORDER BY OrderDate) AS 'RowNumber'
FROM Sales.SalesOrderHeader
)
SELECT *
FROM OrderedOrders
WHERE RowNumber BETWEEN 50 AND 60;
SELECT * FROM comments WHERE ...conditions... LIMIT 1 OFFSET 8
OFFSET is a good thing for MySQL
For SQL Server 2005:
select rank() OVER (ORDER BY c.subject, c.date) as rank, c.subject, c.date
from comments c
where rank = 8
Well, in T-SQL (the dialect for SQL Server) you can do the following:
SELECT TOP 1 *
FROM (SELECT TOP 8 *
FROM Table
ORDER
BY SortField)
ORDER
BY SortField DESC
This way you get the 8th record.
I have read the question & your comments on you would want next 3 blog comments etc.
How is your tables structured?
Assume that you have blog post Id & comment Id is generated in ascending order for each blog post, you could do a SELECT based on the current Id.
e.g. if the blogpostId = 101, you get the top 3 comments order by posted Id. Now lets say, you want to get the next 3 comments - you could do a SELECT WHERE commentId between the last comment id shown TO the comment id - 3
But all that depends on how your tables are defined.
In SQL 2000 where you do not have ROW_NUMBER() function you could use a work-around like this:
SELECT CommentsTableFieldList, IDENTITY(INT, 1,1) as seqNo
INTO #SeqComments
FROM Comments
SELECT * FROM #SeqComments
WHERE seqNo = 8
select top 1 *
from TableName
where ColumnName1 in
(
select top nth ColumnName1
from TableName
order by ColumnName1 desc
)
order by ColumnName1 desc
From the SELECT reference, use the LIMIT keyword:
SELECT * FROM tbl LIMIT 5,10; # Retrieve rows 6-15
SELECT * FROM tbl LIMIT 5; # Retrieve first 5 rows
Note: this is for MySQL, other SQL engines may have a different keyword.
Select from tablename limit nthrow,1;
try This
Let us assume , We want select 5th row of WC_Video Table
And
Select * from (Select Row_Number() over (Order by Uploadedon) as 'rownumber',* from Wc_Video )as Temp where rownumber=5

How to implement LIMIT with SQL Server? [duplicate]

This question already has answers here:
Implement paging (skip / take) functionality with this query
(6 answers)
Closed 1 year ago.
I have this query with MySQL:
select * from table1 LIMIT 10,20
How can I do this with SQL Server?
Starting SQL SERVER 2005, you can do this...
USE AdventureWorks;
GO
WITH OrderedOrders AS
(
SELECT SalesOrderID, OrderDate,
ROW_NUMBER() OVER (ORDER BY OrderDate) AS 'RowNumber'
FROM Sales.SalesOrderHeader
)
SELECT *
FROM OrderedOrders
WHERE RowNumber BETWEEN 10 AND 20;
or something like this for 2000 and below versions...
SELECT TOP 10 * FROM (SELECT TOP 20 FROM Table ORDER BY Id) ORDER BY Id DESC
Starting with SQL SERVER 2012, you can use the OFFSET FETCH Clause:
USE AdventureWorks;
GO
SELECT SalesOrderID, OrderDate
FROM Sales.SalesOrderHeader
ORDER BY SalesOrderID
OFFSET 10 ROWS
FETCH NEXT 10 ROWS ONLY;
GO
http://msdn.microsoft.com/en-us/library/ms188385(v=sql.110).aspx
This may not work correctly when the order by is not unique.
If the query is modified to ORDER BY OrderDate, the result set returned is not as expected.
This is how I limit the results in MS SQL Server 2012:
SELECT *
FROM table1
ORDER BY columnName
OFFSET 10 ROWS FETCH NEXT 10 ROWS ONLY
NOTE: OFFSET can only be used with or in tandem to ORDER BY.
To explain the code line OFFSET xx ROWS FETCH NEXT yy ROW ONLY
The xx is the record/row number you want to start pulling from in the table, i.e: If there are 40 records in table 1, the code above will start pulling from row 10.
The yy is the number of records/rows you want to pull from the table.
To build on the previous example: If table 1 has 40 records and you began pulling from row 10 and grab the NEXT set of 10 (yy).
That would mean, the code above will pull the records from table 1 starting at row 10 and ending at 20. Thus pulling rows 10 - 20.
Check out the link for more info on OFFSET
This is almost a duplicate of a question I asked in October:
Emulate MySQL LIMIT clause in Microsoft SQL Server 2000
If you're using Microsoft SQL Server 2000, there is no good solution. Most people have to resort to capturing the result of the query in a temporary table with a IDENTITY primary key. Then query against the primary key column using a BETWEEN condition.
If you're using Microsoft SQL Server 2005 or later, you have a ROW_NUMBER() function, so you can get the same result but avoid the temporary table.
SELECT t1.*
FROM (
SELECT ROW_NUMBER OVER(ORDER BY id) AS row, t1.*
FROM ( ...original SQL query... ) t1
) t2
WHERE t2.row BETWEEN #offset+1 AND #offset+#count;
You can also write this as a common table expression as shown in #Leon Tayson's answer.
SELECT *
FROM (
SELECT TOP 20
t.*, ROW_NUMBER() OVER (ORDER BY field1) AS rn
FROM table1 t
ORDER BY
field1
) t
WHERE rn > 10
Syntactically MySQL LIMIT query is something like this:
SELECT * FROM table LIMIT OFFSET, ROW_COUNT
This can be translated into Microsoft SQL Server like
SELECT * FROM
(
SELECT TOP #{OFFSET+ROW_COUNT} *, ROW_NUMBER() OVER (ORDER BY (SELECT 1)) AS rnum
FROM table
) a
WHERE rnum > OFFSET
Now your query select * from table1 LIMIT 10,20 will be like this:
SELECT * FROM
(
SELECT TOP 30 *, ROW_NUMBER() OVER (ORDER BY (SELECT 1)) AS rnum
FROM table1
) a
WHERE rnum > 10
SELECT TOP 10 * FROM table;
Is the same as
SELECT * FROM table LIMIT 0,10;
Here's an article about implementing Limit in MsSQL Its a nice read, specially the comments.
This is one of the reasons I try to avoid using MS Server... but anyway. Sometimes you just don't have an option (yei! and I have to use an outdated version!!).
My suggestion is to create a virtual table:
From:
SELECT * FROM table
To:
CREATE VIEW v_table AS
SELECT ROW_NUMBER() OVER (ORDER BY table_key) AS row,* FROM table
Then just query:
SELECT * FROM v_table WHERE row BETWEEN 10 AND 20
If fields are added, or removed, "row" is updated automatically.
The main problem with this option is that ORDER BY is fixed. So if you want a different order, you would have to create another view.
UPDATE
There is another problem with this approach: if you try to filter your data, it won't work as expected. For example, if you do:
SELECT * FROM v_table WHERE field = 'test' AND row BETWEEN 10 AND 20
WHERE becomes limited to those data which are in the rows between 10 and 20 (instead of searching the whole dataset and limiting the output).
In SQL there's no LIMIT keyword exists. If you only need a limited number of rows you should use a TOP keyword which is similar to a LIMIT.
Must try. In below query, you can see group by, order by, Skip rows, and limit rows.
select emp_no , sum(salary_amount) from emp_salary
Group by emp_no
ORDER BY emp_no
OFFSET 5 ROWS -- Skip first 5
FETCH NEXT 10 ROWS ONLY; -- limit to retrieve next 10 row after skiping rows
Easy way
MYSQL:
SELECT 'filds' FROM 'table' WHERE 'where' LIMIT 'offset','per_page'
MSSQL:
SELECT 'filds' FROM 'table' WHERE 'where' ORDER BY 'any' OFFSET 'offset'
ROWS FETCH NEXT 'per_page' ROWS ONLY
ORDER BY is mandatory
This is a multi step approach that will work in SQL2000.
-- Create a temp table to hold the data
CREATE TABLE #foo(rowID int identity(1, 1), myOtherColumns)
INSERT INTO #foo (myColumns) SELECT myData order By MyCriteria
Select * FROM #foo where rowID > 10
SELECT
*
FROM
(
SELECT
top 20 -- ($a) number of records to show
*
FROM
(
SELECT
top 29 -- ($b) last record position
*
FROM
table -- replace this for table name (i.e. "Customer")
ORDER BY
2 ASC
) AS tbl1
ORDER BY
2 DESC
) AS tbl2
ORDER BY
2 ASC;
-- Examples:
-- Show 5 records from position 5:
-- $a = 5;
-- $b = (5 + 5) - 1
-- $b = 9;
-- Show 10 records from position 4:
-- $a = 10;
-- $b = (10 + 4) - 1
-- $b = 13;
-- To calculate $b:
-- $b = ($a + position) - 1
-- For the present exercise we need to:
-- Show 20 records from position 10:
-- $a = 20;
-- $b = (20 + 10) - 1
-- $b = 29;
If your ID is unique identifier type or your id in table is not sorted you must do like this below.
select * from
(select ROW_NUMBER() OVER (ORDER BY (select 0)) AS RowNumber,* from table1) a
where a.RowNumber between 2 and 5
The code will be
select * from limit 2,5
better use this in MSSQLExpress 2017.
SELECT * FROM
(
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 0)) as [Count], * FROM table1
) as a
WHERE [Count] BETWEEN 10 and 20;
--Giving a Column [Count] and assigning every row a unique counting without ordering something then re select again where you can provide your limits.. :)
One of the possible way to get result as below , hope this will help.
declare #start int
declare #end int
SET #start = '5000'; -- 0 , 5000 ,
SET #end = '10000'; -- 5001, 10001
SELECT * FROM (
SELECT TABLE_NAME,TABLE_TYPE, ROW_NUMBER() OVER (ORDER BY TABLE_NAME) as row FROM information_schema.tables
) a WHERE a.row > #start and a.row <= #end
If i remember correctly (it's been a while since i dabbed with SQL Server) you may be able to use something like this: (2005 and up)
SELECT
*
,ROW_NUMBER() OVER(ORDER BY SomeFields) AS [RowNum]
FROM SomeTable
WHERE RowNum BETWEEN 10 AND 20