MySQL存储过程语法
先上一段代码
/* 创建字符串split函数 */ DROP FUNCTION IF EXISTS SPLIT_STR; CREATE FUNCTION SPLIT_STR( x VARCHAR(255), delim VARCHAR(12), pos INT ) RETURNS VARCHAR(255) RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(x, delim, pos), LENGTH(SUBSTRING_INDEX(x, delim, pos -1)) + 1), delim, ''); /* 创建同步店铺头像的存储过程 */ DROP PROCEDURE IF EXISTS SCHEMA_CHANGE_1; DELIMITER $$ CREATE PROCEDURE SCHEMA_CHANGE_1 () BEGIN declare _merchant_id bigint; declare _shop_icon varchar(1500); DECLARE done INT DEFAULT FALSE; Declare maxPicId bigint; declare cur cursor for ( select merchant_id,concat("https://",wenjianlj,".oss-cn-hangzhou.aliyuncs.com/",wenjianmc) as path from ( select t2.merchant_id,SPLIT_STR(shanghutp,"_",1) as guid,SPLIT_STR(shanghutp,"_",2) as verfiCode from (select distinct merchant_id from ( select a.merchant_id as merchant_id, b.id as picId from mdse_shop as a left join mdse_pic as b on a.shop_icon=b.id) t1 where picId is null) t2 inner join yygl_v_shangjiaxx as shangjia on t2.merchant_id=shangjia.shanghubh) t3 inner join xtgy_wenjianccsy as wenjian on t3.guid=wenjian.guid and t3.verfiCode=wenjian.yanzhengma ); DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; -- 监听器 set maxPicId = (select id from mdse_pic order by id desc limit 1); open cur; label:LOOP FETCH cur INTO _merchant_id,_shop_icon; select _merchant_id,_shop_icon; set maxPicId = (maxPicId + 1); insert into mdse_pic(id,path) value(maxPicId,_shop_icon); -- 添加图片记录 update mdse_shop set shop_icon= maxPicId where merchant_id=_merchant_id; -- 门店关联图片记录主键 IF done THEN LEAVE label;END IF; END LOOP label; close cur; END$$ DELIMITER ; CALL SCHEMA_CHANGE_1 ();
1、删除函数语法
drop function 函数名称; 通常会和if exists联合使用。drop function if exists 函数名称;
2、创建函数语法
create function 函数名称( 参数名称 参数类型, 参数名称 参数类型, ... ) returns 返回值类型 return { sql 逻辑语句 }
3、删除存储过程
drop procedure 存储过程名称; 通常会和if exists联合使用,drop procedure if exists 存储过程名称;
4、指定指令结束符 开始
DELIMITER $$
5、重新指定指令结束符为;
DELIMITER ;
6、创建存储过程语法
create procedure 存储过程名称() begin 存储过程内容 end 指令结束符
7、声明存储过程变量
declare 变量名称 变量类型 [default 默认值];
8、修改变量值
set 变量名称=变量值;
9、声明游标
declare 游标名称 cursor for (select查询);
10、声明游标监听器
DECLARE done INT DEFAULT FALSE; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; -- 监听器 如果找不到下一条记录,则把一个标志位变更
11、开启游标,关闭游标
open cur; 操作游标 close cur;
12、遍历游标
label:LOOP FETCH cur INTO _merchant_id,_shop_icon; IF done THEN LEAVE label;END IF; END LOOP label;
13、从游标获取一行记录到变量中
FETCH cur INTO _merchant_id,_shop_icon 注意一点 游标中的列名称不能和变量名重复,负责不会对变量进行赋值
14、调用存储过程
CALL 存储过程名称 ();