MYSQL PL/SQL

一組SQL語(yǔ)句集，速度快，只有首次執(zhí)行需經(jīng)過(guò)編譯和優(yōu)化步驟，后續(xù)被調(diào)用可以直接執(zhí)行

Sample:

DROP PROCEDURE IF EXISTS `proc_adder`;

DELIMITER &&

CREATE DEFINER=`root`@`localhost` PROCEDURE `proc_adder`(IN a int, IN b int, OUT sum int)

BEGIN

DECLARE c int;

/*DECLARE c int DEFAULT 10*/

    if a is null then set a = 0;

    end if;

    if b is null then set b = 0;

    end if;
set sum  = a + b;

END

&&

DELIMITER ;

說(shuō)明：

DEFINER: 創(chuàng)建者

DECLARE: 定義變量

SET:為變量賦

SELECT…INTO語(yǔ)句為變量賦值如下：

SELECT  col_name[,…]  INTO  var_name[,…]  

FROM  table_name  WEHRE  condition

DELIMITER：

MySQL中默認(rèn)的語(yǔ)句結(jié)束符為分號(hào)（;）。存儲(chǔ)過(guò)程中的SQL語(yǔ)句需要分號(hào)（;）來(lái)結(jié)束。為了避免沖突，首先用"DELIMITER &&"將MySQL的結(jié)束符設(shè)置為&&。最后再用"DELIMITER ;"來(lái)將結(jié)束符恢復(fù)成分號(hào)。這與創(chuàng)建觸發(fā)器時(shí)是一樣的。

常用語(yǔ)法：

IF:

IF type = 0 THEN

        set c = 'param is 0';

    ELSEIF type = 1 THEN

        set c = 'param is 1';

    ELSE

        set c = 'param is others, not 0 or 1';

END IF;

CASE:

CASE type

    WHEN 0 THEN

        set c = 'param is 0';

    WHEN 1 THEN

        set c = 'param is 1';

    ELSE

        set c = 'param is others, not 0 or 1';

END CASE;

WHILE:

DECLARE i int;

DECLARE s int;

SET i = 0;

SET s = 0;

WHILE i <= n DO

    set s = s + i;

    set i = i + 1;

END WHILE;