IF ELSE statement in a MySQL Statement?

In an If-Else statement, the condition is evaluated to be true or false depending on the value.

Let us see an example. Firstly, we will create a table. The CREATE command is used to create a table.

 mysql> create table IfelseDemo - > ( - > id int, - > FirstName varchar(100) - > ); Query OK, 0 rows affected (0.46 sec) 

Records are inserted with the help of INSERT command.

 mysql> insert into IfelseDemo values(1,'John'); Query OK, 1 row affected (0.13 sec) mysql> insert into IfelseDemo values(2,'Carol'); Query OK, 1 row affected (0.31 sec) mysql> insert into IfelseDemo values(3,'John'); Query OK, 1 row affected (0.11 sec) mysql> insert into IfelseDemo values(4,'Carol'); Query OK, 1 row affected (0.14 sec) mysql> insert into IfelseDemo values(5,'John'); Query OK, 1 row affected (0.11 sec) 

Displaying all records.

 mysql> select *from IfelseDemo; 

Here is our output.

 +------+-----------+ | id | FirstName | +------+-----------+ | 1 | John | | 2 | Carol | | 3 | John | | 4 | Carol | | 5 | John | +------+-----------+ 5 rows in set (0.00 sec) 

The following is the query for using the if-else statement.

 mysql> SELECT id, FirstName, (case when (id = 2 and FirstName = 'Carol') - > then - > 'Welcome Carol' - > else - > 'You are not Carol with id 2' - >end)as Message from IfelseDemo; 

The following is the output.

 +------+-----------+-----------------------------+ | id | FirstName | Message | +------+-----------+-----------------------------+ | 1 | John | You are not Carol with id 2 | | 2 | Carol | Welcome Carol | | 3 | John | You are not Carol with id 2 | | 4 | Carol | You are not Carol with id 2 | | 5 | john | You are not Carol with id 2 | +------+-----------+-----------------------------+ 5 rows in set (0.00 sec)