MySQL IFNULL ELSE

mysql select ifnull
mcgrailm picture mcgrailm · Jul 9, 2010 · Viewed 103.5k times · Source

I have a select statement where I want to make the select conditional like this:

IFNULL(field_a, field_a, field_b)

so that it checks field a. If a is null then the select would be field b.

Is that possible ?

Answer

OMG Ponies picture OMG Ponies · Jul 9, 2010

Use COALESCE:

SELECT COALESCE(field_a, field_b)

COALESCE is an ANSI standard function that returns the first non-null value from the list of columns specified, processing the columns from left to right. So in the example, if field_a is null, field_b value will be displayed. However, this function will return NULL if there is no non-null value from the columns specified.

It's supported on MySQL (I've used it on 4.1), SQL Server (since v2000), Oracle 9i+...

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