Related
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
I'm looking to some expresion like this (using SQL Server 2008)
SELECT TOP 10 columName FROM tableName
But instead of that I need the values between 10 and 20. And I wonder if there is a way of doing it using only one SELECT statement.
For example this is useless:
SELECT columName FROM
(SELECT ROW_NUMBER() OVER(ORDER BY someId) AS RowNum, * FROM tableName) AS alias
WHERE RowNum BETWEEN 10 AND 20
Because the select inside brackets is already returning all the results, and I'm looking to avoid that, due to performance.
Use SQL Server 2012 to fetch/skip!
SELECT SalesOrderID, SalesOrderDetailID, ProductID, OrderQty, UnitPrice, LineTotal
FROM AdventureWorks2012.Sales.SalesOrderDetail
OFFSET 10 ROWS FETCH NEXT 10 ROWS ONLY;
There's nothing better than you're describing for older versions of sql server. Maybe use CTE, but unlikely to make a difference.
WITH NumberedMyTable AS
(
SELECT
Id,
Value,
ROW_NUMBER() OVER (ORDER BY Id) AS RowNumber
FROM
MyTable
)
SELECT
Id,
Value
FROM
NumberedMyTable
WHERE
RowNumber BETWEEN #From AND #To
or, you can remove top 10 rows and then get next 10 rows, but I double anyone would want to do that.
There is a trick with row_number that does not involve sorting all the rows.
Try this:
SELECT columName
FROM (SELECT ROW_NUMBER() OVER(ORDER BY (select NULL as noorder)) AS RowNum, *
FROM tableName
) as alias
WHERE RowNum BETWEEN 10 AND 20
You cannot use a constant in the order by. However, you can use an expression that evaluates to a constant. SQL Server recognizes this and just returns the rows as encountered, properly enumerated.
Why do you think SQL Server would evaluate the entire inner query? Assuming your sort column is indexed, it'll just read the first 20 values. If you're really nervous you could do this:
Select
Id
From (
Select Top 20 -- note top 20
Row_Number() Over(Order By Id) As RowNum,
Id
From
dbo.Test
Order By
Id
) As alias
Where
RowNum Between 10 And 20
Order By
Id
but I'm pretty sure the query plan is the same either way.
(Really) Fixed as per Aaron's comment.
http://sqlfiddle.com/#!3/db162/6
One more option
SELECT TOP(11) columName
FROM dbo.tableName
ORDER BY
CASE WHEN ROW_NUMBER() OVER (ORDER BY someId) BETWEEN 10 AND 20
THEN ROW_NUMBER() OVER (ORDER BY someId) ELSE NULL END DESC
You could create a temp table that is ordered the way you want like:
SELECT ROW_NUMBER() OVER(ORDER BY someId) AS RowNum, * FROM tableName
into ##tempTable
...
That way you have an ordered list of rows.
and can just query by row number the subsequent times instead of doing the inner query multiple times.
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
I'm trying to do something like :
SELECT * FROM table LIMIT 10,20
or
SELECT * FROM table LIMIT 10 OFFSET 10
but using SQL Server
The only solution I found looks like overkill:
SELECT * FROM (
SELECT *, ROW_NUMBER() OVER (ORDER BY name) as row FROM sys.databases
) a WHERE row > 5 and row <= 10
I also found:
SELECT TOP 10 * FROM stuff;
... but it's not what I want to do since I can't specify the starting limit.
Is there another way for me to do that ?
Also, just curious, is there a reason why doesn't SQL Server support the LIMIT function or something similar? I don't want to be mean, but that really sounds like something a DBMS needs ... If it does, then I'm sorry for being so ignorant! I've been working with MySQL and SQL+ for the past 5 years so...
For SQL Server 2012 + you can use.
SELECT *
FROM sys.databases
ORDER BY name
OFFSET 5 ROWS
FETCH NEXT 5 ROWS ONLY
The LIMIT clause is not part of standard SQL. It's supported as a vendor extension to SQL by MySQL, PostgreSQL, and SQLite.
Other brands of database may have similar features (e.g. TOP in Microsoft SQL Server), but these don't always work identically.
It's hard to use TOP in Microsoft SQL Server to mimic the LIMIT clause. There are cases where it just doesn't work.
The solution you showed, using ROW_NUMBER() is available in Microsoft SQL Server 2005 and later. This is the best solution (for now) that works solely as part of the query.
Another solution is to use TOP to fetch the first count + offset rows, and then use the API to seek past the first offset rows.
See also:
"Emulate MySQL LIMIT clause in Microsoft SQL Server 2000"
"Paging of Large Resultsets in ASP.NET"
as you found, this is the preferred sql server method:
SELECT * FROM (
SELECT *, ROW_NUMBER() OVER (ORDER BY name) as row FROM sys.databases
) a WHERE a.row > 5 and a.row <= 10
How about this?
SET ROWCOUNT 10
SELECT TOP 20 *
FROM sys.databases
ORDER BY database_id DESC
It gives you the last 10 rows of the first 20 rows. One drawback is that the order is reversed, but, at least it's easy to remember.
If you are using SQL Server 2012+ vote for Martin Smith's answer and use the OFFSET and FETCH NEXT extensions to ORDER BY,
If you are unfortunate enough to be stuck with an earlier version, you could do something like this,
WITH Rows AS
(
SELECT
ROW_NUMBER() OVER (ORDER BY [dbo].[SomeColumn]) [Row]
, *
FROM
[dbo].[SomeTable]
)
SELECT TOP 10
*
FROM
Rows
WHERE Row > 10
I believe is functionaly equivalent to
SELECT * FROM SomeTable LIMIT 10 OFFSET 10 ORDER BY SomeColumn
and the best performing way I know of doing it in TSQL, before MS SQL 2012.
If there are very many rows you may get better performance using a temp table instead of a CTE.
Unfortunately, the ROW_NUMBER() is the best you can do. It's actually more correct, because the results of a limit or top clause don't really have meaning without respect to some specific order. But it's still a pain to do.
Update: Sql Server 2012 adds a limit -like feature via OFFSET and FETCH keywords. This is the ansi-standard approach, as opposed to LIMIT, which is a non-standard MySql extension.
SELECT TOP 10 *
FROM TABLE
WHERE IDCOLUMN NOT IN (SELECT TOP 10 IDCOLUMN FROM TABLE)
Should give records 11-20.
Probably not too efficient if incrementing to get further pages, and not sure how it might be affected by ordering.
Might have to specify this in both WHERE statements.
A good way is to create a procedure:
create proc pagination (#startfrom int ,#endto int) as
SELECT * FROM (
SELECT *, ROW_NUMBER() OVER (ORDER BY name desc) as row FROM sys.databases
) a WHERE a.row > #startfrom and a.row <= #endto
just like limit 0,2
///////////////
execute pagination 0,4
Just for the record solution that works across most database engines though might not be the most efficient:
Select Top (ReturnCount) *
From (
Select Top (SkipCount + ReturnCount) *
From SourceTable
Order By ReverseSortCondition
) ReverseSorted
Order By SortCondition
Pelase note: the last page would still contain ReturnCount rows no matter what SkipCount is. But that might be a good thing in many cases.
The equivalent of LIMIT is SET ROWCOUNT, but if you want generic pagination it's better to write a query like this:
;WITH Results_CTE AS
(
SELECT
Col1, Col2, ...,
ROW_NUMBER() OVER (ORDER BY SortCol1, SortCol2, ...) AS RowNum
FROM Table
WHERE <whatever>
)
SELECT *
FROM Results_CTE
WHERE RowNum >= #Offset
AND RowNum < #Offset + #Limit
select * from (select id,name,ROW_NUMBER() OVER (ORDER BY id asc) as row
from tableName1) tbl1
where tbl1.row>=10 and tbl1.row<=15
Will print rows from 10 to 15.
So far this format is what is working for me (not the best performance though):
SELECT TOP {desired amount of rows} *
FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY {order columns} asc)__row__ FROM {table})tmp
WHERE __row__ > {offset row count}
A note on the side, paginating over dynamic data can lead to strange/unexpected results.
From the MS SQL Server online documentation (http://technet.microsoft.com/en-us/library/ms186734.aspx
), here is their example that I have tested and works, for retrieving a specific set of rows. ROW_NUMBER requires an OVER, but you can order by whatever you like:
WITH OrderedOrders AS
(
SELECT SalesOrderID, OrderDate,
ROW_NUMBER() OVER (ORDER BY OrderDate) AS RowNumber
FROM Sales.SalesOrderHeader
)
SELECT SalesOrderID, OrderDate, RowNumber
FROM OrderedOrders
WHERE RowNumber BETWEEN 50 AND 60;
Use all SQL server:
;with tbl as (SELECT ROW_NUMBER() over(order by(select 1)) as RowIndex,* from table)
select top 10 * from tbl where RowIndex>=10
SELECT * FROM users WHERE Id Between 15 and 25
it will print from 15 to 25 as like limit in MYSQl
In SQL Server, TOP may be used to return the first n number of rows in a query. For example, SELECT TOP 100 * FROM users ORDER BY id might be used to return the first 100 people that registered for a site. (This is not necessarily the best way, I am just using it as an example).
My question is - What is the equivalent to TOP in other databases, such as Oracle, MySQL, PostgreSQL, etc? If there is not an equivalent keyword, what workarounds can you recommend to achieve the same result?
To select first 100 rows:
MySQL and PostgreSQL:
SELECT *
FROM Table
ORDER BY
column
LIMIT 100
Oracle:
SELECT *
FROM (
SELECT t.*
FROM table
ORDER BY
column
)
WHERE rownum <= 100
Note that you need a subquery here. If you don't add a subquery, ROWNUM will select first 10 rows in random order and then sort them by column.
To select rows between 100 and 300:
MySQL:
SELECT *
FROM TABLE
ORDER BY
column
LIMIT 100, 200
PostgreSQL:
SELECT *
FROM Table
ORDER BY
column
OFFSET 100 LIMIT 200
Oracle:
SELECT *
FROM (
SELECT t.*, ROW_NUMBER() OVER (ORER BY column) AS rn
FROM table
)
WHERE rn >= 100
AND rownum <= 200
Note that an attempt to simplify it with ROWNUM BETWEEN 100 AND 200 (as opposed to rn BETWEEN 100 AND 200 in the outer query) will return nothing in Oracle!
RN BETWEEN 100 AND 200 will work in Oracle too but is less efficient.
See the article in my blog for performance details:
Oracle: ROW_NUMBER vs ROWNUM
For Postgres and MySQL it's the LIMIT keyword.
SELECT *
FROM users
ORDER BY id
LIMIT 100;
This is standard SQL (Oracle and SQL Server implement it). This is an example of returning up to 100 rows:
SELECT ID_CONTROL FROM (SELECT ROW_NUMBER() OVER (ORDER BY ID_CONTROL)
ROWNUMBER, ID_CONTROL FROM IWS_CONTROL WHERE
CURRENT_STATE = 15 AND CURRENT_STATUS=0) A WHERE ROWNUMBER <= 100)
In SQL Anywhere, it's the same as SQL Server:
SELECT TOP 100 * FROM users ORDER BY id
You can even start in the middle of the result set if you want:
SELECT TOP 100 START AT 50 * FROM users ORDER BY id
gets the 50th through 150th rows of the result set.
LIMIT 100
as in
SELECT * FROM foo ORDER BY bar LIMIT 100
You can use RANK() and DENSE_RANK() in Oracle. Here is a link to AskTom website explaining how to to pagination and top-n queries with DENSE_RANK in Oracle.
Oracle:
select * from (select * from foo ORDER BY bar) where rownum < 100
With a nice explanation on how to make it work in AskTom.
In Ingres the same query would by:
select First 100 * from foo ORDER BY bar
Ingres question was already answered in StackOverflow before.
In DB2 you would make your query look like this:
SELECT * FROM tblData FETCH FIRST 10 ROWS ONLY;
In Oracle you want to use a TOP-N query.
For example:
select *
from (SELECT *
FROM foo
where foo_id=[number]
order by foo_id desc)
where rownum <= 3
This will get you the top three results (because I order by desc in the sub query)