COALESCE Function

COALESCE returns the first non-NULL element provided.

Signatures 

Parameter Type Description
val Any The values you want to check.

Return value 

All elements of the parameters for coalesce must be of the same type; coalesce returns that type, or NULL.

Examples 

SELECT coalesce(NULL, 3, 2, 1) AS coalesce_res;
 res
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   3