Join Question

[mnmdesigns]

Hi all,

I need some help in writing a query. I have two tables A and B. Both the tables should ideally have rows the ID field. Table B can have more than one rows associated to that ID but there should be atleast one row. Unfortunately, that is not the case. I need to find out all the ID's that exist in Table A but not in Table B. Can anybody please help me? Thanks!

 

[JohnDTampaBay]

--- Option 1: This may perform slightly better than option 2
SELECT a.ID
FROM TableA AS a
WHERE NOT EXISTS(
SELECT * FROM TableB AS b
WHERE b.ID = a.ID)

--- Option 2
SELECT DISTINCT a.ID
FROM TableA AS a
LEFT OUTER JOIN TableB AS b
ON a.ID = b.ID
WHERE b.ID IS NULL


--John
-----------------------------------
Behold! As a wild ass in the desert
go forth I to do my work.
--Gurnie Hallock (Dune)