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Implement multiple COUNT() in a single MySQL query
For this, use CASE statement. Let us first create a table −
mysql> create table DemoTable -> ( -> LastName varchar(100) -> ); Query OK, 0 rows affected (0.60 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values('Smith');
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable values('Brown');
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable values('Brown');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable values('Smith');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values('Taylor');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values('Taylor');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values('Miller');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values('Miller');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable values('Miller');
Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
Output
This will produce the following output −
+----------+ | LastName | +----------+ | Smith | | Brown | | Brown | | Smith | | Taylor | | Taylor | | Miller | | Miller | | Miller | +----------+ 9 rows in set (0.00 sec)
Following is the query to implement multiple COUNT() methods in one query −
mysql> select COUNT(CASE WHEN LastName='Smith' THEN 1 END) AS TotalFrequency, -> COUNT(CASE WHEN LastName='Brown' THEN 1 END) AS TotalFrequency, -> COUNT(CASE WHEN LastName='Taylor' THEN 1 END) AS TotalFrequency, -> COUNT(CASE WHEN LastName='Miller' THEN 1 END) AS TotalFrequency -> from DemoTable;
Output
This will produce the following output −
+----------------+----------------+----------------+----------------+ | TotalFrequency | TotalFrequency | TotalFrequency | TotalFrequency | +----------------+----------------+----------------+----------------+ | 2 | 2 | 2 | 3 | +----------------+----------------+----------------+----------------+ 1 row in set (0.00 sec)
Updated on: 30-Jun-2020
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