MySQL Tutorial/Procedure Function/Call
Содержание
Call another function
mysql>
mysql> delimiter $$
mysql>
mysql> CREATE FUNCTION isodd(input_number int)
-> RETURNS int
-> BEGIN
-> DECLARE v_isodd INT;
->
-> IF MOD(input_number,2)=0 THEN
-> SET v_isodd=FALSE;
-> ELSE
-> SET v_isodd=TRUE;
-> END IF;
->
-> RETURN(v_isodd);
->
-> END$$
Query OK, 0 rows affected (0.01 sec)
mysql>
mysql> CREATE PROCEDURE myProc(aNumber int)
-> Begin
-> IF (isodd(aNumber)) THEN
-> SELECT " is odd";
-> ELSE
-> SELECT " is even";
-> END IF;
-> END$$
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql> delimiter ;
mysql>
mysql>
mysql> call myProc(2);
+----------+
| is even |
+----------+
| is even |
+----------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
mysql>
mysql> call myProc(1);
+---------+
| is odd |
+---------+
| is odd |
+---------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> call myProc(4);
+----------+
| is even |
+----------+
| is even |
+----------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql> drop function isodd;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
Call another procedure
From the MySQL client, you use the CALL statement to execute a procedure, providing the procedure name and correct number of arguments.
CALL [database.]<procedure name> ([<parameter>, <parameter>, -]);
Call another procedure to pass the error code
mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE myProc()
-> MODIFIES SQL DATA
-> BEGIN
-> DECLARE l_status VARCHAR(20);
->
-> CALL myProc1(l_status);
-> IF l_status="Duplicate Entry" THEN
-> SELECT CONCAT("Warning: using existing definition for location ") AS warning;
-> END IF;
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> CREATE PROCEDURE myProc1(OUT out_status VARCHAR(30))
-> BEGIN
-> set out_status = "Duplicate Entry";
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
mysql> delimiter ;
mysql> call myProc();
+--------------------------------------------------+
| warning |
+--------------------------------------------------+
| Warning: using existing definition for location |
+--------------------------------------------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql> drop procedure myProc1;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
Call another procedure with parameter
mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE myProc(id int)
-> BEGIN
->
-> SELECT "in proc"+ id;
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> CREATE PROCEDURE myProc1()
-> BEGIN
->
-> call myProc(1);
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
mysql>
mysql> call myProc1();
+---------------+
| "in proc"+ id |
+---------------+
| 1 |
+---------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected, 1 warning (0.02 sec)
mysql>
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql> drop procedure myProc1;
Query OK, 0 rows affected (0.00 sec)
mysql>
CALL Statement Syntax
CALL sp_name([parameter[,...]])
CALL sp_name[()]
The CALL statement invokes a procedure.
CALL can pass back values to its caller.
A client program can call the ROW_COUNT() function to get the count of affected rows.
Nested function call
mysql>
mysql> CREATE TABLE Employee(
-> id int,
-> first_name VARCHAR(15),
-> last_name VARCHAR(15),
-> start_date DATE,
-> end_date DATE,
-> salary FLOAT(8,2),
-> city VARCHAR(10),
-> description VARCHAR(15)
-> );
Query OK, 0 rows affected (0.03 sec)
mysql>
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values (1,"Jason", "Martin", "19960725", "20060725", 1234.56, "Toronto", "Programmer");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values(2,"Alison", "Mathews", "19760321", "19860221", 6661.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values(3,"James", "Smith", "19781212", "19900315", 6544.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values(4,"Celia", "Rice", "19821024", "19990421", 2344.78, "Vancouver","Manager");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values(5,"Robert", "Black", "19840115", "19980808", 2334.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values(6,"Linda", "Green", "19870730", "19960104", 4322.78,"New York", "Tester");
Query OK, 1 row affected (0.02 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values(7,"David", "Larry", "19901231", "19980212", 7897.78,"New York", "Manager");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date, salary, City, Description)
-> values(8,"James", "Cat", "19960917", "20020415", 1232.78,"Vancouver", "Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> select * from Employee;
+------+------------+-----------+------------+------------+---------+-----------+-------------+
| id | first_name | last_name | start_date | end_date | salary | city | description |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
| 1 | Jason | Martin | 1996-07-25 | 2006-07-25 | 1234.56 | Toronto | Programmer |
| 2 | Alison | Mathews | 1976-03-21 | 1986-02-21 | 6661.78 | Vancouver | Tester |
| 3 | James | Smith | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester |
| 4 | Celia | Rice | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager |
| 5 | Robert | Black | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester |
| 6 | Linda | Green | 1987-07-30 | 1996-01-04 | 4322.78 | New York | Tester |
| 7 | David | Larry | 1990-12-31 | 1998-02-12 | 7897.78 | New York | Manager |
| 8 | James | Cat | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
8 rows in set (0.00 sec)
mysql>
mysql>
mysql>
mysql> delimiter $$
mysql>
mysql> CREATE FUNCTION myFunction(in_rep_id INT)
-> RETURNS INT
-> READS SQL DATA
-> BEGIN
-> DECLARE customer_count INT;
->
-> SELECT COUNT(*)
-> INTO customer_count
-> FROM employee
-> WHERE id=in_rep_id;
->
-> RETURN(customer_count);
->
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
mysql> CREATE PROCEDURE myProc(in_employee_id INT)
-> BEGIN
-> IF myFunction(in_employee_id) > 0 THEN
-> select "greater than 0";
-> ELSE
-> select "less or equals than 0";
-> END IF;
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
mysql>
mysql> call myProc(1);
+----------------+
| greater than 0 |
+----------------+
| greater than 0 |
+----------------+
1 row in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql> drop function myFunction;
Query OK, 0 rows affected (0.00 sec)
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
mysql>
mysql>
mysql> drop table Employee;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>