Let us first create a table −
mysql> create table DemoTable ( Score int ); Query OK, 0 rows affected (0.65 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values(45); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(29); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(56); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(24); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(32); Query OK, 1 row affected (0.09 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+-------+ | Score | +-------+ | 45 | | 29 | | 56 | | 24 | | 32 | +-------+ 5 rows in set (0.00 sec)
Following is the query to update MySQL column by subtracting a value with some conditions −
mysql> update DemoTable set Score=Score-2 where Score > 30; Query OK, 3 rows affected (0.14 sec) Rows matched: 3 Changed: 3 Warnings: 0
Let us check the table records once again −
mysql> select *from DemoTable;
This will produce the following output −
+-------+ | Score | +-------+ | 43 | | 29 | | 54 | | 24 | | 30 | +-------+ 5 rows in set (0.00 sec)