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Find the count of EMPTY or NULL columns in a MySQL table?
Let us first create a table −
mysql> create table DemoTable781 ( Name varchar(100) ); Query OK, 0 rows affected (0.66 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable781 values('');
Query OK, 1 row affected (0.29 sec)
mysql> insert into DemoTable781 values('Chris');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable781 values('');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable781 values(null);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable781 values(null);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable781 values('');
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable781 values(null);
Query OK, 1 row affected (0.28 sec)Display all records from the table using select statement −
mysql> select *from DemoTable781;
This will produce the following output -
+-------+ | Name | +-------+ | | | Chris | | | | NULL | | NULL | | | | NULL | +-------+ 7 rows in set (0.00 sec)
Here is the query to find the count of EMPTY or NULL columns in a MySQL table −
mysql> (select SUM(CASE when Name IS NULL THEN 1 ELSE 0 END) AS NullCountAndEmptyCount from DemoTable781) UNION ALL (select SUM(CASE when Name='' THEN 1 ELSE 0 END) AS NullCountAndEmptyCount from DemoTable781);
This will produce the following output -
+------------------------+ | NullCountAndEmptyCount | +------------------------+ | 3 | | 3 | +------------------------+ 2 rows in set (0.00 sec)
Updated on: 09-Sep-2019
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