To enhance the accepted answer code, check out mine. The code will start by deleting 1000 rows from the table at a time, and then increase the batch size by 10% after each iteration. This way, the code will delete more rows as the table gets smaller and reduce the number of loops needed. The variable @count will still store the number of rows affected by each delete statement and the loop will stop when it becomes zero.

DECLARE @batch_size INT = 10000
DECLARE @count INT = 1
WHILE @count > 0
BEGIN
    ;WITH CTE AS
    (
    SELECT TOP (@batch_size) *
    FROM [mytab]
    ORDER BY a1
    )
    DELETE FROM CTE

    SET @count = @@ROWCOUNT

    -- Increase the batch size by 10% after each iteration
    SET @batch_size = @batch_size * 1.1
END

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

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.

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

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

SET ROWCOUNT 1000;

DELETE FROM [MyTable] WHERE .....

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.

I agree with the Hamed elahi and Glorfindel.

My suggestion to add is you can delete and update using aliases

/* 
  given a table bi_customer_actions
  with a field bca_delete_flag of tinyint or bit
    and a field bca_add_date of datetime

  note: the *if 1=1* structure allows me to fold them and turn them on and off
 */
declare
        @Nrows int = 1000

if 1=1 /* testing the inner select */
begin
  select top (@Nrows) * 
    from bi_customer_actions
    where bca_delete_flag = 1
    order by bca_add_date
end

if 1=1 /* delete or update or select */
begin
  --select bca.*
  --update bca  set bca_delete_flag = 0
  delete bca
    from (
      select top (@Nrows) * 
        from bi_customer_actions
        where bca_delete_flag = 1
        order by bca_add_date
    ) as bca
end