MySQL Tutorial/Procedure Function/Call
Содержание
Call another function
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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$$
Query OK, 0 rows affected (0.02 sec) mysql> mysql> delimiter ; mysql> mysql> mysql> call myProc(2); +----------+ | is even | +----------+ | is even | +----------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.01 sec) mysql> mysql> call myProc(1); +---------+ | is odd | +---------+ | is odd | +---------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) mysql> mysql> call myProc(4); +----------+ | is even | +----------+ | is even | +----------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) mysql> mysql> mysql> drop procedure myProc; Query OK, 0 rows affected (0.00 sec) mysql> drop function isodd; Query OK, 0 rows affected (0.00 sec) mysql> mysql></source>
Call another procedure
From the MySQL client, you use the CALL statement to execute a procedure, providing the procedure name and correct number of arguments.
<source lang="sql">
CALL [database.]<procedure name> ([<parameter>, <parameter>, -]);</source>
Call another procedure to pass the error code
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mysql> mysql> delimiter $$ 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></source>
Call another procedure with parameter
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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></source>
CALL Statement Syntax
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CALL sp_name([parameter[,...]])
CALL sp_name[()]</source>
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
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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></source>