How to get the count of both present and absent students for a year in MySQL?

For this, you can use IF() along with aggregate function SUM(). Let us first create a table −

mysql> create table DemoTable1617
    -> (
    -> Attendance varchar(20),
    -> CurrentYear int
    -> );
Query OK, 0 rows affected (0.48 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1617 values('Present',2019);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable1617 values('Absent',2019);
Query OK, 1 row affected (0.20 sec)
mysql> insert into DemoTable1617 values('Absent',2017);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable1617 values('Present',2019);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable1617 values('Present',2018);
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable1617 values('Present',2019);
Query OK, 1 row affected (0.14 sec)

Display all records from the table using select statement

mysql> select * from DemoTable1617;

This will produce the following output −

+------------+-------------+
| Attendance | CurrentYear |
+------------+-------------+
| Present    |        2019 |
| Absent     |        2019 |
| Absent     |        2017 |
| Present    |        2019 |
| Present    |        2018 |
| Present    |        2019 |
+------------+-------------+
6 rows in set (0.00 sec)

Following is the query to get the count of both present and absent students for a year

mysql> select sum(if(Attendance='Present',1,0)) as Present ,
    -> sum(if(Attendance='Absent',1,0)) as Absent
    -> from DemoTable1617
    -> where CurrentYear LIKE '2019%';

This will produce the following output −

+---------+--------+
| Present | Absent |
+---------+--------+
|       3 |      1 |
+---------+--------+
1 row in set (0.00 sec)

AmitDiwan

Published on 17-Dec-2019 06:24:38

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