[ale] [OT] Left Join SQL help...

[greg at turnstep.com]

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Try using 'IS NULL' instead of '= NULL'.

Null is never equal to anything, not even itself:

SELECT CASE WHEN '' IS NULL THEN 1 ELSE 0 END;

SELECT CASE WHEN '' = NULL THEN 1 ELSE 0 END;

SELECT CASE WHEN NULL = NULL THEN 1 ELSE 0 END;

SELECT CASE WHEN NULL IS NULL THEN 1 ELSE 0 END;

Only the last will return a "1"

- --
Greg Sabino Mullane  greg at turnstep.com
PGP Key: 0x14964AC8 200304020755

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