identifying common elements of two columns of two tables

krontrex · #1 (**permalink**) 09-05-11, 05:48

I am trying to get the list of ids that appears in two tables:
select id1 from table1 where id1 IN (SELECT id2 from table2).
However this query does not give the desired results.
Why?

shammat · #2 (**permalink**) 09-05-11, 05:56

Can id2 be NULL? If yes, use the following

Code:

select id1 
from table1 
where id1 IN (SELECT id2 
              from table2
              WHERE id2 <> NULL)

krontrex · #3 (**permalink**) 09-05-11, 06:58

Is there any faster way to solve this? I mean to check if the elements of some columns are also in a column of some other table?
Thanks

shammat · #4 (**permalink**) 09-05-11, 07:29

What exactly do you mean with "elements of some columns"?

Please show us the table definitions (as CREATE TABLE statements), some sample data (as INSERT INTO statements) and the output you expect to see.

And please use [code] tags to make your SQL readable.
For details on how to use the tag, please see: http://www.dbforums.com/misc.php?do=bbcode

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