COALESCE() - Finding First Non-NULL Value

Q

How to find the first non-NULL value from a list using the COALESCE() function?

✍: FYIcenter.com

A

COALESCE(val1, val2, ...) is a MySQL built-in function that returns the first non-NULL value from a given list of values. For example:

SELECT COALESCE(NULL, 'FYI', NULL, 3.14);
  -- +-----------------------------------+
  -- | COALESCE(NULL, 'FYI', NULL, 3.14) |
  -- +-----------------------------------+
  -- | FYI                               |
  -- +-----------------------------------+

Reference information of the COALESCE() function:

COALESCE(val1, val2, ...): val
  Returns the first non-NULL value from a given list of values.

Arguments, return value and availability:
  val1, val2, ...: One or more values to be examined.
  val: Return value. The first non-NULL value.
  Available since MySQL 4.0.

⇒ CONVERT() - Character Set Conversion

⇐ CAST() - Casting Expression to Value

⇑ MySQL Functions for Miscellaneous Purposes

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