Subtracting a number from a single MySQL column value?

For this, just update the table and subtract. Let us first create a table −

mysql> create table DemoTable1372    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.77 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1372 values(500); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1372 values(100); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable1372 values(900); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1372 values(1000); Query OK, 1 row affected (0.32 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1372;

This will produce the following output −

+-------+ | Value | +-------+ |   500 | |   100 | |   900 | |  1000 | +-------+ 4 rows in set (0.00 sec)

Following is the query to subtract a number from a single MySQL column value −

mysql> update DemoTable1372 set Value=Value-50 where Value=900; Query OK, 1 row affected (0.52 sec) Rows matched: 1  Changed: 1 Warnings: 0

Let us check the table records once again −

mysql> select * from DemoTable1372;

This will produce the following output −

+-------+ | Value | +-------+ |   500 | |   100 | |   850 | |  1000 | +-------+ 4 rows in set (0.00 sec)