difference between IS NULL and = NULL
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I altered a sql script the other day to handle for a column containing NULLs. Basically, in the case of a NULL I wanted the value 'Other' to take its' place.
When I gave the condition = NULL, the NULLs remained. When I gave the condition IS NULL then the NULLS were replaced with the value 'Other' as was desirable.
So far I have only come up with the following link when googling: http://www.sqlservercentral.com/articles/T-SQL/understandingthedifferencebetweenisnull/871/ and it refers to setting variables to NULL and memory allocation.
Can someone explain difference between IS NULL and = NULL when using conditional statements?
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KoldCoffee (5/22/2013)
I altered a sql script the other day to handle for a column containing NULLs. Basically, in the case of a NULL I wanted the value 'Other' to take its' place.When I gave the condition = NULL, the NULLs remained. When I gave the condition IS NULL then the NULLS were replaced with the value 'Other' as was desirable.
So far I have only come up with the following link when googling: http://www.sqlservercentral.com/articles/T-SQL/understandingthedifferencebetweenisnull/871/ and it refers to setting variables to NULL and memory allocation.
Can someone explain difference between IS NULL and = NULL when using conditional statements?
Think of NULL as "I don't know"
= NULL
Does the value in my column match a value that I don't know?
Answer: I don't know
IS NULL
Is the value in my column a value that I don't know?
Answer: Yes
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Sean has the best explanation I could give. When testing for a null value, you want to use "Is Null", or INULL() or COALESCE(). Those are functions designed to work with null values.
= NULL is unknown. It could be equal; it could not.
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Thank you Sean and Steve!
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