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How to use a single MySQL query to count column values ignoring null?
For this, you can COUNT() method, which does not include NULL value. Let us first create a table −
mysql> create table DemoTable -> ( -> Name varchar(100), -> CountryName varchar(100) -> ); Query OK, 0 rows affected (0.49 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values('John',null);
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable values('Chris','US');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable values('Robert',null);
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable values('Bob','UK');
Query OK, 1 row affected (0.57 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
Output
This will produce the following output −
+--------+-------------+ | Name | CountryName | +--------+-------------+ | John | NULL | | Chris | US | | Robert | NULL | | Bob | UK | +--------+-------------+ 4 rows in set (0.00 sec)
Here is the query to use COUNT() and ignore NULL −
mysql> select count(Name) AS TotalName,count(CountryName) AS CountryWhichIsNotNull from DemoTable;
Output
This will produce the following output −
+-----------+-----------------------+ | TotalName | CountryWhichIsNotNull | +-----------+-----------------------+ | 4 | 2 | +-----------+-----------------------+ 1 row in set (0.00 sec)
Updated on: 30-Jun-2020
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