SQL: select all records not selected by another query

Question

I am looking for an SQL query to select all records not selected by another query on the same table. Specifically I want to select all records which have duplicates of a pa

Answer 1

Specifically I want to select all records which have duplicates of a particular field('fieldA') and then delete all but one of those records.

In that case, join it:

delete x 
from myTable x
 join myTable z on x.field = z.field
where x.id > z.id

Answer 2

If you change your not IN sub SELECT statement to only return one column (ID), it should work -

http://blog.sqlauthority.com/2008/04/22/sql-server-better-performance-left-join-or-not-in/

Answer 3

Something like:

SELECT id FROM table WHERE id IN (
    SELECT MIN(id) FROM table GROUP BY fieldA HAVING COUNT(*) > 1
)