To count boolean field values within a single query, you can use CASE statement. Let us create a demo table for our example −
mysql> create table countBooleanFieldDemo -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentFirstName varchar(20), -> isPassed tinyint(1) -> ); Query OK, 0 rows affected (0.63 sec)
Insert some records in the table using insert command.
The query is as follows −
mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Larry',0); Query OK, 1 row affected (0.12 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Mike',1); Query OK, 1 row affected (0.17 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Sam',0); Query OK, 1 row affected (0.21 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Carol',1); Query OK, 1 row affected (0.15 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Bob',1); Query OK, 1 row affected (0.16 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('David',1); Query OK, 1 row affected (0.13 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Ramit',0); Query OK, 1 row affected (0.28 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Chris',1); Query OK, 1 row affected (0.20 sec) mysql> insert into countBooleanFieldDemo(StudentFirstName,isPassed) values('Robert',1); Query OK, 1 row affected (0.16 sec)
Display all records from the table using select statement.
The query is as follows −
mysql> select *from countBooleanFieldDemo;
Here is the output −
+-----------+------------------+----------+ | StudentId | StudentFirstName | isPassed | +-----------+------------------+----------+ | 1 | Larry | 0 | | 2 | Mike | 1 | | 3 | Sam | 0 | | 4 | Carol | 1 | | 5 | Bob | 1 | | 6 | David | 1 | | 7 | Ramit | 0 | | 8 | Chris | 1 | | 9 | Robert | 1 | +-----------+------------------+----------+ 9 rows in set (0.00 sec)
Here is the query to count boolean field values within a single query −
mysql> select sum(isPassed= 1) as `True`, sum(isPassed = 0) as `False`, -> ( -> case when sum(isPassed = 1) > 0 then sum(isPassed = 0) / sum(isPassed = 1) -> end -> )As TotalPercentage -> from countBooleanFieldDemo;
The following is The output −
+------+-------+-----------------+ | True | False | TotalPercentage | +------+-------+-----------------+ | 6 | 3 | 0.5000 | +------+-------+-----------------+ 1 row in set (0.00 sec)