ISNULL
Description
The ISNULL function returns an INT which indicates whether the input value is NULL. If the input value is NULL, the function returns 1; otherwise it returns 0.
ISNULL should not be confused with the predicate operator IS NULL, which returns a Boolean.
ISNULL can be applied to any data type.
Typically, ISNULL is used inside a condition, for example in a CASE WHEN or FILTER statement. However, as the function returns an INT, it is not restricted to be used with those statements.
In order to map NULL values to a different value, COALESCE or REMAP_VALUES can also be used instead of a CASE WHEN combined with ISNULL.
Syntax
ISNULL ( table.column )
Examples
[1] Return the result of the ISNULL operator for a STRING column and use it inside a CASE WHEN condition: | ||||||||||||||||||||||||||||
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[2] Return the result of the ISNULL operator for a INT column and use it inside a CASE WHEN condition: | ||||||||||||||||||||||||||||
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