Decrease a row value by 1 in MySQL?

You can increase and decrease row value by 1 in MySQL using UPDATE command. The syntax is as follows −

UPDATE yourTableName set yourColumnName = yourColumnName-1 where condition;

Let us create a table to decrease row value by 1. The following is the query −

mysql> create table IncrementAndDecrementValue
   −> (
   −> UserId int,
   −> UserScores int
   −> );
Query OK, 0 rows affected (0.60 sec)

Insert some records in the table using insert command. The query is as follows −

mysql> insert into IncrementAndDecrementValue values(101,20000);
Query OK, 1 row affected (0.13 sec)

mysql> insert into IncrementAndDecrementValue values(102,30000);
Query OK, 1 row affected (0.20 sec)

mysql> insert into IncrementAndDecrementValue values(103,40000);
Query OK, 1 row affected (0.11 sec)

Display all records from the table using select statement. The query is as follows −

mysql> select *from IncrementAndDecrementValue;

The following is the output;

+--------+------------+
| UserId | UserScores |
+--------+------------+
|    101 | 20000      |
|    102 | 30000      |
|    103 | 40000      |
+--------+------------+
3 rows in set (0.00 sec)

Here is the query to decrease the UserScores value by 1 with where condition.

mysql> update IncrementAndDecrementValue set UserScores = UserScores-1 where UserId = 103;
Query OK, 1 row affected (0.41 sec)
Rows matched: 1 Changed: 1 Warnings: 0

Let us check whether the value is updated or not. The query is as follows −

mysql> select *from IncrementAndDecrementValue;

The following is the output displaying that we have successfully decremented a row value −

+--------+------------+
| UserId | UserScores |
+--------+------------+
|    101 | 20000      |
|    102 | 30000      |
|    103 | 39999      |
+--------+------------+
3 rows in set (0.00 sec)