The syntax is as follows to perform UPDATE using IF condition in MySQL −
update yourTableName set yourColumnName =if(yourColumnName =yourOldValue,yourNewValue,yourColumnName);
To understand the above syntax, let us create a table. The query to create a table is as follows −
mysql> create table updateIfConditionDemo -> ( -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(20), -> UserAge int -> ); Query OK, 0 rows affected (4 min 0.59 sec)
Now you can insert some records in the table using insert command. The query is as follows −
mysql> insert into updateIfConditionDemo(UserName,UserAge) values('Larry',23); Query OK, 1 row affected (0.11 sec) mysql> insert into updateIfConditionDemo(UserName,UserAge) values('Mike',21); Query OK, 1 row affected (0.20 sec) mysql> insert into updateIfConditionDemo(UserName,UserAge) values('Sam',23); Query OK, 1 row affected (0.15 sec) mysql> insert into updateIfConditionDemo(UserName,UserAge) values('David',23); Query OK, 1 row affected (0.14 sec) mysql> insert into updateIfConditionDemo(UserName,UserAge) values('Maxwell',23); Query OK, 1 row affected (0.18 sec)
Display all records from the table using select statement. The query is as follows −
mysql> select *from updateIfConditionDemo;
Here is the output −
+--------+----------+---------+ | UserId | UserName | UserAge | +--------+----------+---------+ | 1 | Larry | 23 | | 2 | Mike | 21 | | 3 | Sam | 23 | | 4 | David | 23 | | 5 | Maxwell | 23 | +--------+----------+---------+ 5 rows in set (0.00 sec)
Here is the query to update using IF condition −
mysql> update updateIfConditionDemo set UserAge =if(UserAge =23,26,UserAge); Query OK, 4 rows affected (0.20 sec) Rows matched: 5 Changed: 4 Warnings: 0
Let us check the table records once again. The UserAge has been updated from 23 to 26 −
mysql> select *from updateIfConditionDemo;
Here is the output −
+--------+----------+---------+ | UserId | UserName | UserAge | +--------+----------+---------+ | 1 | Larry | 26 | | 2 | Mike | 21 | | 3 | Sam | 26 | | 4 | David | 26 | | 5 | Maxwell | 26 | +--------+----------+---------+ 5 rows in set (0.00 sec)