A NULL is a value for which comparison yields neither a true nor false result.NULL = NULL is not true. It’s not false either. The outcome of any comparison of one value to a NULL value is a NULL result.
If you want to check a Column for NULL value then use the following query
Query1
SELECT IFNULL(ColName, '') AS Names FROM TableName
Query2
SELECT CASE WHEN ColName IS NULL THEN '' ELSE ColName END AS TableName FROM Test
Query3
SELECT COALESCE(ColName, 0) as 'ColName' FROM TableName;
Query4
SELECT IF(ColName IS NULL, '', ColName) FROM TableName