How can we store a value in user-defined variable?
We can store a value in a user-defined variable in a statement and then refer to it afterward in other statements. Followings are the ways to store a value in user-defined variable −
With SET statement
we can store a user-defined variable by issuing a SET statement as follows −
Syntax
SET @var_name = expr[, @var_name = expr]…
In this @var_name is the variable name which consists of alphanumeric characters from current character set. We can use either = or := assignment operator with SET statement.
For example following queries can store the user variables with SET statement −
mysql> SET @value = 500;
Query OK, 0 rows affected (0.00 sec)
mysql> SET @value := 500;
Query OK, 0 rows affected (0.00 sec)
mysql> SET @value = 500, @value1=550;
Query OK, 0 rows affected (0.00 sec)
Without SET statement
Without the SET statement, we can also assign a value to a user variable in statements as follows −
mysql> select @value,@value1, @value2 := @value+@value1;
+--------+---------+---------------------------+
| @value | @value1 | @value2 := @value+@value1 |
+--------+---------+---------------------------+
| 500 | 550 | 1050 |
+--------+---------+---------------------------+
1 row in set (0.00 sec)
In this case, we must have to use := assignment operator.
Published on 20-Feb-2018 06:57:39
