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I want to create a table in MySQL that will have a Unique constrant...

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lich12345

lich12345

Programmer
Sep 27, 2001
1
US
I want to create a table in MySQL that will have a Unique constrant, however I also want the option of putting in NULL. In other words when inserting data into this column it allows me to enter NULL or other then that it has to be unique data.

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Jeremy
 
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Hi Jeremy,

I am sorry, but you cannot do this with RDBMS. Every value has to be unique, and NULL is a value of its own, so two NULLS will be a duplicate key failure. You can either make the column a Unique contraint, or a NULL, but they are mutually exclusive.

Tim
 
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