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Count number of occurrences of records in a MySQL table and display the result in a new column?
For this, use COUNT(*) along with GROUP BY clause. Let us first create a table −
mysql> create table DemoTable1942 ( Value int ); Query OK, 0 rows affected (0.00 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1942 values(1); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1942 values(2); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1942 values(3); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1942 values(2); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1942 values(3); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1942 values(3); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1942 values(1); Query OK, 1 row affected (0.00 sec)
Display all records from the table using select statement −
mysql> select * from DemoTable1942;
This will produce the following output −
+-------+ | Value | +-------+ | 1 | | 2 | | 3 | | 2 | | 3 | | 3 | | 1 | +-------+ 7 rows in set (0.00 sec)
Here is the query to count number of occurrences:
mysql> select Value, count(*) from DemoTable1942 group by Value;
This will produce the following output −
+-------+----------+ | Value | count(*) | +-------+----------+ | 1 | 2 | | 2 | 2 | | 3 | 3 | +-------+----------+ 3 rows in set (0.00 sec)
Updated on: 31-Dec-2019
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