Mysql存储过程案例集合

注:使用的工具为SQLyog

壹、while简单使用（替换字符串中的字符,和REPLACE效果一样）

注: 这里没有使用REPLACE函数

1、创建存储过程

DROP  PROCEDURE  IF EXISTS replaceStr;
DELIMITER $$
CREATE  PROCEDURE `replaceStr`(INOUT oldStr VARCHAR(1024), IN replace1 VARCHAR(16), IN replace2 VARCHAR(16))  
 BEGIN  
 SET @i=0;  
 -- 获取参数replace1出现的次数
 SET @count = CHAR_LENGTH(oldStr)-CHAR_LENGTH(REPLACE(oldStr, replace1, '')); 
 -- 先申明一个变量存放替换之后的字符串
 SET @newStr = ''; 
  
 WHILE @i <= @count  
 DO      
    SET @i=@i+1;  
    IF(@i != 1) THEN
        SELECT CONCAT(@newStr, replace2, SUBSTRING_INDEX(SUBSTRING_INDEX(oldStr, replace1 ,@i), replace1 ,-1)) INTO @newStr;
    ELSE 
        SELECT CONCAT(@newStr, SUBSTRING_INDEX(SUBSTRING_INDEX(oldStr, replace1, @i), replace1, -1)) INTO @newStr;
    END IF;
    
 END WHILE;  
 -- 把替换之后的字符串赋给旧字符串变量
 SET oldStr = @newStr;
END; 

2、调用存储过程

SET @arrayStr = '1 2 3 4 5 6 7';
CALL replaceStr(@arrayStr, ' ', '-');
SELECT @arrayStr;

3、执行结果

1-2-3-4-5-6-7

---

贰、游标简单使用

1、建立一张学生表

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(256) DEFAULT NULL,
  `class` varchar(256) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
 
-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES ('1', '张三', '1班');
INSERT INTO `student` VALUES ('2', '李四', '2班');
INSERT INTO `student` VALUES ('3', '王五', '3班');
INSERT INTO `student` VALUES ('4', '麻子', '1班');
INSERT INTO `student` VALUES ('5', '老王', '3班');

2、建立存储过程

DROP  PROCEDURE  IF EXISTS fors;
DELIMITER $$
CREATE PROCEDURE fors(OUT namess VARCHAR(1024))
BEGIN
    DECLARE a VARCHAR(500);
    DECLARE Done, nameCount INT DEFAULT 0 ;
    DECLARE rs CURSOR FOR SELECT NAME FROM student;
    DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET Done = 1 ;
    
    -- 不申明结果为NULL
    SET namess = '';
    
    -- 打开游标
    OPEN rs;
        FETCH NEXT FROM rs INTO a;
        REPEAT
            SET nameCount = nameCount + 1 ;
            IF(nameCount != 1 ) THEN
        SELECT CONCAT(namess,',' , a) INTO namess;
        ELSE
        SELECT CONCAT(namess, a) INTO namess;
            END IF;
        FETCH NEXT FROM rs INTO a;
    UNTIL Done END REPEAT;
    CLOSE rs;
END

3、调用存储过程

CALL fors(@names);


SELECT @names;

4、执行结果

张三,李四,王五,麻子,老王

---

叁、游标+while简单使用

1、建立一张学生表

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(256) DEFAULT NULL,
  `class` varchar(256) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
 
-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES ('1', '张三', '1班');
INSERT INTO `student` VALUES ('2', '李四', '2班');
INSERT INTO `student` VALUES ('3', '王五', '3班');
INSERT INTO `student` VALUES ('4', '麻子', '1班');
INSERT INTO `student` VALUES ('5', '老王', '3班');

2、建立存储过程 

DROP  PROCEDURE  IF EXISTS whileFor;
DELIMITER $$ 
CREATE PROCEDURE whileFor(OUT namess VARCHAR(1024))
BEGIN
    DECLARE a VARCHAR(500);
    DECLARE i , j , Done INT DEFAULT 0 ;
    -- 申明游标
    DECLARE rs CURSOR FOR SELECT NAME FROM student;
    DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET Done = 1 ;
    SET namess = '' , i = 0 , j = 1;
    -- 循环四次
    WHILE (j < 5) DO
    -- 如果不是第一次，我们这里加一个|区分
    IF(j > 1) THEN 
       SELECT CONCAT(namess,'|') INTO namess; 
    END IF;
    
    -- 打开游标
        OPEN rs;
            FETCH NEXT FROM rs INTO a;
            REPEAT
                SET i = i + 1 ; 
                IF(i != 1 ) THEN
                    SELECT CONCAT(namess,',' , a) INTO namess;
                ELSE
                    SELECT CONCAT(namess , a) INTO namess;
                END IF;
                 
            FETCH NEXT FROM rs INTO a;
        UNTIL Done END REPEAT;
        CLOSE rs;
        SET j = j + 1;
        SET Done = 0 ; 
        SET i = 0 ;
    END WHILE;
END

3、调用存储过程

CALL whileFor(@names);

SELECT @names;

  4、执行结果

张三,李四,王五,麻子,老王|张三,李四,王五,麻子,老王|张三,李四,王五,麻子,老王|张三,李四,王五,麻子,老王

---

肆、游标+游标简单使用

1、建立一张学生表

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(256) DEFAULT NULL,
  `class` varchar(256) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
 
-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES ('1', '张三', '1班');
INSERT INTO `student` VALUES ('2', '李四', '2班');
INSERT INTO `student` VALUES ('3', '王五', '3班');
INSERT INTO `student` VALUES ('4', '麻子', '1班');
INSERT INTO `student` VALUES ('5', '老王', '3班');

2、建立存储过程 

DROP  PROCEDURE  IF EXISTS forFor;
DELIMITER $$
CREATE  PROCEDURE   forFor(OUT classNames VARCHAR(1024))   
BEGIN
-- 班级名、姓名
DECLARE  classs , namess VARCHAR(500);
-- 班级数量、该班级下面学生的数量、班级变量++、学生变量++ 
DECLARE  classNumber , nameNumber, classCount , nameCount INT  DEFAULT   0;
-- 建立两个游标，第一个游标用来存储班级、第二个用来存储学生姓名
DECLARE  class_csr CURSOR  FOR  SELECT  class FROM   student GROUP  BY  class;
DECLARE  name_csr CURSOR   FOR  SELECT  NAME  FROM  student WHERE  class = classs ; 
-- 获取按班级分组之后的数量
SELECT   COUNT(*) INTO classNumber FROM  (SELECT   COUNT(*) FROM  student GROUP  BY  class) t;
SET classNames = '' ;


   -- 打开班级游标
   OPEN   class_csr;
    -- 开始班级游标循环
    class_loop: LOOP  
    
        FETCH   class_csr INTO  classs ;
        SET  classCount = classCount +1 ;
        IF(classCount != 1 ) THEN
        SELECT CONCAT(classNames,',' , classs, '(') INTO classNames;
        ELSE
        SELECT CONCAT(classNames, classs, '(') INTO classNames;
            END IF;
            
            -- 获取该班级下面学生的数量
        SELECT  COUNT(*) INTO  nameNumber FROM  student WHERE   class = classs;
        
        -- 打开学生游标
        OPEN  name_csr;
        -- 开始学生游标循环
        name_loop: LOOP  
        FETCH  name_csr INTO  namess;
            SET  nameCount = nameCount +1 ;
            
            IF(nameCount != 1 ) THEN
                SELECT CONCAT(classNames,',' , namess) INTO classNames;
            ELSE
                SELECT CONCAT(classNames , namess) INTO classNames;
            END IF;
            
            -- 如果学生变量等于学生数量，那么就终止该游标（第一个）
            IF(nameCount = nameNumber) THEN
                LEAVE name_loop;
            END  IF;
        -- 结束学生游标循环
        END LOOP name_loop;
        -- 关闭学生游标
        CLOSE  name_csr;
        
        SET  nameCount = 0 ;
        SELECT CONCAT(classNames , ')') INTO classNames;
        
        -- 如果班级变量等于班级数量，那么就终止该游标（第二个）
        IF(classCount = classNumber) THEN
        LEAVE class_loop;
        END  IF;
    
    -- 结束班级游标循环
    END LOOP class_loop;
  -- 关闭班级游标
  CLOSE   class_csr;
  
  
END  ;

3、调用存储过程 

CALL forFor(@classNames);


SELECT @classNames;

4、执行结果

1班(张三,麻子),2班(李四),3班(王五,老王)