My monetdb table has over 100k rows. I want to select the last n rows from the table. Will it be possible to query only the last n records without scanning the entire table?
for Transact SQL:
SELECT *
FROM [your_table] AS tbl
ORDER BY 1 DESC
TOP n
or others (SQL Standard):
SELECT *
FROM [your_table] AS tbl
ORDER BY 1 DESC
LIMIT n
The only reliable way of doing this is by having a column with an increasing time stamp or id value that you can ORDER BY.
Especially if there are no deletes, MonetDB will notice that this column is sorted and use this fact to quickly locate the latest rows.
I want to fire a Query "SELECT * FROM TABLE" but select only from row N+1. Any idea on how to do this?
For SQL Server 2012 and above, use this:
SELECT *
FROM Sales.SalesOrderHeader
ORDER BY OrderDate
OFFSET (#Skip) ROWS FETCH NEXT (#Take) ROWS ONLY
https://stackoverflow.com/a/19669165/1883345
SQL Server:
select * from table
except
select top N * from table
Oracle up to 11.2:
select * from table
minus
select * from table where rownum <= N
with TableWithNum as (
select t.*, rownum as Num
from Table t
)
select * from TableWithNum where Num > N
Oracle 12.1 and later (following standard ANSI SQL)
select *
from table
order by some_column
offset x rows
fetch first y rows only
They may meet your needs more or less.
There is no direct way to do what you want by SQL.
However, it is not a design flaw, in my opinion.
SQL is not supposed to be used like this.
In relational databases, a table represents a relation, which is a set by definition. A set contains unordered elements.
Also, don't rely on the physical order of the records. The row order is not guaranteed by the RDBMS.
If the ordering of the records is important, you'd better add a column such as `Num' to the table, and use the following query. This is more natural.
select *
from Table
where Num > N
order by Num
Query: in sql-server
DECLARE #N INT = 5 --Any random number
SELECT * FROM (
SELECT ROW_NUMBER() OVER(ORDER BY ID) AS RoNum
, ID --Add any fields needed here (or replace ID by *)
FROM TABLE_NAME
) AS tbl
WHERE #N < RoNum
ORDER BY tbl.ID
This will give rows of Table, where rownumber is starting from #N + 1.
In order to do this in SQL Server, you must order the query by a column, so you can specify the rows you want.
Example:
select * from table order by [some_column]
offset 10 rows
FETCH NEXT 10 rows only
Do you want something like in LINQ skip 5 and take 10?
SELECT TOP(10) * FROM MY_TABLE
WHERE ID not in (SELECT TOP(5) ID From My_TABLE ORDER BY ID)
ORDER BY ID;
This approach will work in any SQL version. You need to stablish some order (by Id for example) so all rows are provided in a predictable manner.
I know it's quite late now to answer the query. But I have a little different solution than the others which I believe has better performance because no comparisons are performed in the SQL query only sorting is done. You can see its considerable performance improvement basically when value of SKIP is LARGE enough.
Best performance but only for SQL Server 2012 and above. Originally from #Majid Basirati's answer which is worth mentioning again.
DECLARE #Skip INT = 2, #Take INT = 2
SELECT * FROM TABLE_NAME
ORDER BY ID ASC
OFFSET (#Skip) ROWS FETCH NEXT (#Take) ROWS ONLY
Not as Good as the first one but compatible with SQL Server 2005 and above.
DECLARE #Skip INT = 2, #Take INT = 2
SELECT * FROM
(
SELECT TOP (#Take) * FROM
(
SELECT TOP (#Take + #Skip) * FROM TABLE_NAME
ORDER BY ID ASC
) T1
ORDER BY ID DESC
) T2
ORDER BY ID ASC
What about this:
SELECT * FROM table LIMIT 50 OFFSET 1
This works with all DBRM/SQL, it is standard ANSI:
SELECT *
FROM owner.tablename A
WHERE condition
AND n+1 <= (
SELECT COUNT(DISTINCT b.column_order)
FROM owner.tablename B
WHERE condition
AND b.column_order>a.column_order
)
ORDER BY a.column_order DESC
PostgreSQL: OFFSET without LIMIT
This syntax is supported, and it is in my opinion the cleanest API compared to other SQL implementations as it does not introduce any new keywords:
SELECT * FROM mytable ORDER BY mycol ASC OFFSET 1
that should definitely be standardized.
The fact that this is allowed can be seen from: https://www.postgresql.org/docs/13/sql-select.html since LIMIT and OFFSET can be given independently, since OFFSET is not a sub-clause of LIMIT in the syntax specification:
[ LIMIT { count | ALL } ]
[ OFFSET start [ ROW | ROWS ] ]
SQLite: negative limit
OFFSET requires LIMIT in that DBMS, but dummy negative values mean no limit. Not as nice as PostgreSQL, but it works:
SELECT * FROM mytable ORDER BY mycol ASC LIMIT -1 OFFSET 1
Asked at: SQLite with skip (offset) only (not limit)
Documented at: https://sqlite.org/lang_select.html
If the LIMIT expression evaluates to a negative value, then there is no upper bound on the number of rows returned.
MySQL: use a huge limit number
Terrible API design, the documentation actually recommends it:
SELECT * FROM tbl LIMIT 1,18446744073709551615;
Asked at: MySQL skip first 10 results
Node.js Sequelize ORM implements it
That ORM allows e.g. findAll({offset: without limit:, and implements workarounds such as the ones mentioned above for each different DBMS.
In Faircom SQL (which is a pseudo MySQL), i can do this in a super simple SQL Statement, just as follows:
SELECT SKIP 10 * FROM TABLE ORDER BY Id
Obviously you can just replace 10 with any declared variable of your desire.
I don't have access to MS SQL or other platforms, but I'll be really surprised MS SQL doesn't support something like this.
DECLARE #Skip int= 2, #Take int= 2
SELECT * FROM TABLE_NAME
ORDER BY Column_Name
OFFSET (#Skip) ROWS FETCH NEXT (#Take) ROWS ONLY
try below query it's work
SELECT * FROM `my_table` WHERE id != (SELECT id From my_table LIMIT 1)
Hope this will help
You can also use OFFSET to remove the 1st record from your query result like this-
Example - find the second max salary from the employee table
select distinct salary from employee order by salary desc limit 1 OFFSET 1
For SQL Server 2012 and later versions, the best method is #MajidBasirati's answer.
I also loved #CarlosToledo's answer, it's not limited to any SQL Server version but it's missing Order By Clauses. Without them, it may return wrong results.
For SQL Server 2008 and later I would use Common Table Expressions for better performance.
-- This example omits first 10 records and select next 5 records
;WITH MyCTE(Id) as
(
SELECT TOP (10) Id
FROM MY_TABLE
ORDER BY Id
)
SELECT TOP (5) *
FROM MY_TABLE
INNER JOIN MyCTE ON (MyCTE.Id <> MY_TABLE.Id)
ORDER BY Id
In Oracle PL/SQL I was used to write:
SELECT * FROM MY_TABLE WHERE ROWNUM <= 100;
in order to fetch only the first 100 records of the table named MY_TABLE.
What could be the equivalent SELECT statement in SQL SERVER?
In SQL-Server You can Use TOP to select the no. of rows.
SELECT TOP 100 * FROM MY_TABLE
select top 100 * from tbl
column name is required or use *
SELECT TOP 100 * FROM TABLE
You can also filter rows by using where class
SELECT TOP 100 * FROM YOURTABLE WHERE YOURCONDITION
In SQL Server 2012, you can use OFFSET and FETCH to determine which rows to return. They're documented under ORDER BY; This makes sense since asking for 100 rows, when tables are by definition unordered, gives unpredictable results.
Similarly, if you use other's answers, re: TOP, you should also have an ORDER BY clause, or else it's not defined which rows will be returned.
SELECT TOP 100 * FROM MY_TABLE
Sorry if I misunderstood.
Edit: Must be faster
I have been asked for a SQL statement to retrieve an arbitrary number of rows, randomly selected, from a data table in a database hosted on Oracle RDB on VMS.
In MS SQL, it would simply be:
SELECT TOP 5 *
FROM MyTable
ORDER BY NEWID()
But I cannot find an equivalent method for RDB/VMS.
"Proper" Oracle would be:
ORDER BY dbms_random.VALUE
However, that does not appear to be supoprted in RDB on VMS.
Any insights would be greatly appreciated.
SELECT *
FROM MyTable
ORDER BY NEWID()
LIMIT to 5
I don't know the "RDB way" to do it, but if the records have sequential IDs, find out the hightest-number ID and then by scripting generate a random list of IDs to fetch. Something like:
SELECT TOP 1 FROM mytable ORDER BY id DESC;
Then in Python: records = random.sample(range(topId), 5)
I want to fetch records from a table in my sql server database in parts. Like, in one query I want to see first 1000 records, in next query next 1000 records. Likewise..
Is it possible with sql server ? I am using sql server 2008. While googling, I found LIMIT clause for mysql, but it does not work for sql server. So can any one give in Sql. Please help.
First 1000 records:
SELECT TOP 1000 *
FROM mytable
ORDER BY
mycolumn
General solution (supports offset)
SELECT *
FROM (
SELECT *,
ROW_NUMBER() OVER (ORDER BY mycolumn) rn
FROM mytable
) q
WHERE rn BETWEEN 1001 AND 2000
ORDER BY
mycolumn
Have also a look at T-sql: how to perform optimised Paging?