COUNT CASE and WHEN statement in MySQL

How to use COUNT CASE and WHEN statement in MySQL query, to count when data is NULL and when it is not NULL in one MySQL query?

How do you use case in count?

CASE can be used in conjunction with SUM to return a count of only those items matching a pre-defined condition. (This is similar to COUNTIF in Excel.) The trick is to return binary results indicating matches, so the "1"s returned for matching entries can be summed for a count of the total number of matches.

Use:

SELECT SUM(CASE               WHEN t.your_column IS NULL THEN 1              ELSE 0            END) AS numNull,        SUM(CASE               WHEN t.your_column IS NOT NULL THEN 1              ELSE 0            END) AS numNotNull   FROM YOUR_TABLE t

That will sum up the column NULL & not NULL for the entire table. It's likely you need a GROUP BY clause, depending on needs.