SQL/MySQL/Procedure Function/IF statement — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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(нет различий)
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Версия 16:46, 26 мая 2010
Содержание
Check version with if statement
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mysql> mysql> delimiter $$ mysql> mysql> CREATE PROCEDURE myProc()
-> BEGIN -> -> IF (INSTR(version(),"alpha")>0) THEN -> SELECT "Alpha release of MySQL"; -> ELSEIF (INSTR(version(),"beta")>0) THEN -> SELECT "Beta release of MySQL"; -> ELSE -> SELECT "Production release of MySQL"; -> END IF; -> -> -> END$$
Query OK, 0 rows affected (0.00 sec) mysql> mysql> delimiter ; mysql> mysql> call myProc(); +-----------------------------+ | Production release of MySQL | +-----------------------------+ | Production release of MySQL | +-----------------------------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) mysql> mysql> drop procedure myProc; Query OK, 0 rows affected (0.00 sec) mysql> mysql>
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IF
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mysql> mysql> mysql> DELIMITER // mysql> CREATE FUNCTION delivery_day_shipping (delivery_day INT(1)) RETURNS INT(2)
-> BEGIN -> -> DECLARE shipping_cost INT(2) DEFAULT 0; -> -> IF delivery_day = 1 THEN -> SET shipping_cost = 20; -> ELSEIF delivery_day = 2 THEN -> SET shipping_cost = 15; -> ELSEIF delivery_day = 3 THEN -> SET shipping_cost = 10; -> ELSE -> SET shipping_cost = 5; -> END IF; -> -> RETURN shipping_cost; -> -> END -> //
ERROR 1304 (42000): FUNCTION delivery_day_shipping already exists mysql> DELIMITER ; mysql> mysql>
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IF statement in a LOOP statement
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mysql> mysql> delimiter $$ mysql> mysql> CREATE PROCEDURE myProc()
-> BEGIN -> -> DECLARE i int; -> SET i=0; -> loop1: REPEAT -> SET i=i+1; -> IF MOD(i,2)<>0 THEN /*Even number - try again*/ -> SELECT CONCAT(i," is an odd number"); -> END IF; -> UNTIL i >= 10 -> END REPEAT; -> END$$
Query OK, 0 rows affected (0.00 sec) mysql> mysql> delimiter ; mysql> call myProc(); +-------------------------------+ | CONCAT(i," is an odd number") | +-------------------------------+ | 1 is an odd number | +-------------------------------+ 1 row in set (0.00 sec) +-------------------------------+ | CONCAT(i," is an odd number") | +-------------------------------+ | 3 is an odd number | +-------------------------------+ 1 row in set (0.33 sec) +-------------------------------+ | CONCAT(i," is an odd number") | +-------------------------------+ | 5 is an odd number | +-------------------------------+ 1 row in set (0.33 sec) +-------------------------------+ | CONCAT(i," is an odd number") | +-------------------------------+ | 7 is an odd number | +-------------------------------+ 1 row in set (0.34 sec) +-------------------------------+ | CONCAT(i," is an odd number") | +-------------------------------+ | 9 is an odd number | +-------------------------------+ 1 row in set (0.34 sec) Query OK, 0 rows affected (0.34 sec) mysql> drop procedure myProc; Query OK, 0 rows affected (0.00 sec) mysql>
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If statement with ELSEIF and ELSE
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mysql> mysql> delimiter $$ mysql> CREATE PROCEDURE myProc(normal_price NUMERIC(8,2),OUT discount_price NUMERIC(8,2))
-> NO SQL -> BEGIN -> IF (normal_price>500) THEN -> SET discount_price=normal_price*.8; -> ELSEIF (normal_price>100) THEN -> SET discount_price=normal_price*.9; -> -> ELSE -> SET discount_price=normal_price; -> END IF; -> select discount_price; -> END$$
Query OK, 0 rows affected (0.00 sec) mysql> delimiter ; mysql> mysql> set @p = 600; Query OK, 0 rows affected (0.00 sec) mysql> set @dp = 0; Query OK, 0 rows affected (0.00 sec) mysql> mysql> call myProc(@p, @dp); +----------------+ | discount_price | +----------------+ | 480.00 | +----------------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) mysql> select @dp; +--------+ | @dp | +--------+ | 480.00 | +--------+ 1 row in set (0.00 sec) mysql> drop procedure myProc; Query OK, 0 rows affected (0.00 sec) mysql>
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Using OR in an IF statement
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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 (0.01 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 (0.01 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 (0.02 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 (0.00 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 $$ mysql> CREATE PROCEDURE myProc(in_employee_id INT, in_new_salary NUMERIC(8,2))
-> DETERMINISTIC -> BEGIN -> IF in_new_salary <5000 OR in_new_salary > 500000 THEN -> SELECT "Illegal salary; salary must be between $5,000 and $500,000"; -> ELSE -> UPDATE employee SET salary=in_new_salary -> WHERE id=in_employee_id; -> END IF; -> END$$
Query OK, 0 rows affected (0.00 sec) mysql> delimiter ; mysql> mysql> call myProc(1, 6000); Query OK, 1 row affected (0.02 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 | 6000.00 | 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> call myProc(1,4000); +------------------------------------------------------------+ | Illegal salary; salary must be between $5,000 and $500,000 | +------------------------------------------------------------+ | Illegal salary; salary must be between $5,000 and $500,000 | +------------------------------------------------------------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.01 sec) mysql> mysql> DROP PROCEDURE myProc; Query OK, 0 rows affected (0.02 sec) mysql> mysql> mysql> mysql> mysql> mysql> drop table Employee; Query OK, 0 rows affected (0.00 sec) mysql> mysql>
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