How do I pass a variable to a MySQL script?

You can pass a variable to a MySQL script using session variable. First you need to set a session variable using SET command. After that you need to pass that variable to a MySQL script.
The syntax is as follows −
First Step: Use of Set command.
SET @anyVariableName − = ’yourValue’;
Second Step: Pass a variable to a MySQL script.
UPDATE yourTableName SET yourColumnName1 = yourColumnName1+integerValue WHERE yourColumnName2 = @anyVariableName;
To understand the above syntax, let us create a table. The query to create a table is as follows −
mysql> create table Employee_Information
   -> (
   -> EmployeeId int NOT NULL AUTO_INCREMENT,
   -> EmployeeName varchar(20) NOT NULL,
   -> EmployeeSalary int,
   -> EmployeeStatus varchar(20),
   -> PRIMARY KEY(EmployeeId)
   -> );
Query OK, 0 rows affected (0.53 sec)
Now you can insert some records in the table using insert command. The query is as follows −
mysql> insert into Employee_Information(EmployeeName,EmployeeSalary,EmployeeStatus) values('Sam',17650,'FullTime');
Query OK, 1 row affected (0.13 sec)

mysql> insert into Employee_Information(EmployeeName,EmployeeSalary,EmployeeStatus) values('Carol',12000,'Trainee');
Query OK, 1 row affected (0.18 sec)

mysql> insert into Employee_Information(EmployeeName,EmployeeSalary,EmployeeStatus) values('Bob',17650,'FullTime');
Query OK, 1 row affected (0.20 sec)

mysql> insert into Employee_Information(EmployeeName,EmployeeSalary,EmployeeStatus) values('Mike',12000,'Trainee');
Query OK, 1 row affected (0.14 sec)

mysql> insert into Employee_Information(EmployeeName,EmployeeSalary,EmployeeStatus) values('John',17650,'FullTime');
Query OK, 1 row affected (0.16 sec)
Display all records from the table using select statement.
mysql> select *from Employee_Information;
The following is the output −
+------------+--------------+----------------+----------------+
| EmployeeId | EmployeeName | EmployeeSalary | EmployeeStatus |
+------------+--------------+----------------+----------------+
|          1 | Sam          |          17650 | FullTime       |
|          2 | Carol        |          12000 | Trainee        |
|          3 | Bob          |          17650 | FullTime       |
|          4 | Mike         |          12000 | Trainee        |
|          5 | John         |          17650 | FullTime       |
+------------+--------------+----------------+----------------+
5 rows in set (0.00 sec)
The following is the query to pass a variable to a MySQL script −
mysql> set @EmpStatus − = 'FullTime';
Query OK, 0 rows affected (0.03 sec)

mysql> update Employee_Information set EmployeeSalary = EmployeeSalary+6500 where EmployeeStatus = @EmpStatus;
Query OK, 3 rows affected (0.18 sec)
Rows matched − 3 Changed − 3 Warnings − 0
Now check the table records once again using SELECT statement. I have incremented the EmployeeSalary with 6500, for the employees working FullTime.
The query is as follows −
mysql> select *from Employee_Information;
The following is the output −
+------------+--------------+----------------+----------------+
| EmployeeId | EmployeeName | EmployeeSalary | EmployeeStatus |
+------------+--------------+----------------+----------------+
|          1 | Sam          |          24150 | FullTime       |
|          2 | Carol        |          12000 | Trainee        |
|          3 | Bob          |          24150 | FullTime       |
|          4 | Mike         |          12000 | Trainee        |
|          5 | John         |          24150 | FullTime       |
+------------+--------------+----------------+----------------+
5 rows in set (0.00 sec)