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Help selecting what is NOT in two tables


Best Answer Jessica, 04 March 2013 - 01:22 PM

SELECT ClassDetail.CLID
FROM ClassDetail
LEFT JOIN Classes
ON Classes.CLID = ClassDetail.CLID
WHERE Classes.CLID IS NULL
Not tested. Go to the full post


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#1 benphp

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Posted 04 March 2013 - 01:18 PM

I have two tables:

 

Classes

CLID | CLDate

 

ClassDetail

CLID | Description | Instructor

 

 

I'm trying to figure out a single SQL statement that would return all CLIDs that exist in ClassDetail but NOT in Classes.

 

I'm in the process of fudging it in PHP, but I know there's a better way...

 

Thanks!



#2 Jessica

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Posted 04 March 2013 - 01:22 PM   Best Answer

SELECT ClassDetail.CLID
FROM ClassDetail
LEFT JOIN Classes
ON Classes.CLID = ClassDetail.CLID
WHERE Classes.CLID IS NULL
Not tested.
My goal in replying to posts is to help you become a better programmer, including learning how to debug your own code and research problems. For that reason, rather than posting the solution, I reply with tips and hints on how to find the solution yourself. See below for useful links when you get stuck.

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#3 benphp

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Posted 04 March 2013 - 01:29 PM

That does it. Thanks!






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