How to delete the top 1000 rows from a table using Sql Server 2008?

Question

I have a table in SQL Server. I would like to delete the top 1000 rows from it. However, I tried this, but I instead of just deleting the top 1000 rows it deleted all the rows in the table.

Here is the code:

delete from [mytab] 
select top 1000 
a1,a2,a3
from [mytab]

Answer 1

The code you tried is in fact two statements. A DELETE followed by a SELECT.

You don't define TOP as ordered by what.

For a specific ordering criteria deleting from a CTE or similar table expression is the most efficient way.

;WITH CTE AS
(
SELECT TOP 1000 *
FROM [mytab]
ORDER BY a1
)
DELETE FROM CTE

Answer 2

May be better for sql2005+ to use:

DELETE TOP (1000)
FROM [MyTab]
WHERE YourConditions

For Sql2000:

DELETE FROM [MyTab]
WHERE YourIdField IN 
(
  SELECT TOP 1000 
    YourIdField 
  FROM [MyTab]
  WHERE YourConditions
)

BUT

If you want to delete specific subset of rows instead of arbitrary subset, you should explicitly specify order to subquery:

DELETE FROM [MyTab]
WHERE YourIdField IN 
(
  SELECT TOP 1000 
    YourIdField 
  FROM [MyTab]
  WHERE YourConditions
  ORDER BY ExplicitSortOrder
)

Thanks tp @gbn for mentioning and demanding the more clear and exact answer.

Answer 3

As defined in the link below, you can delete in a straight forward manner

USE AdventureWorks2008R2;
GO
DELETE TOP (20) 
FROM Purchasing.PurchaseOrderDetail
WHERE DueDate < '20020701';
GO

http://technet.microsoft.com/en-us/library/ms175486(v=sql.105).aspx

Answer 4

delete from [mytab]
where [mytab].primarykeyid in
(
select top 1000 primarykeyid
from [mytab]
)

Answer 5

SET ROWCOUNT 1000;

DELETE FROM [MyTable] WHERE .....

Answer 6

It is fast. Try it:

DELETE FROM YourTABLE
FROM (SELECT TOP XX PK FROM YourTABLE) tbl
WHERE YourTABLE.PK = tbl.PK

Replace YourTABLE by table name, XX by a number, for example 1000, pk is the name of the primary key field of your table.