mysql 过程和函数语法学习笔记

CREATE DEFINER=`root`@`%` PROCEDURE `test`(`num` int)
BEGIN
    /*定义变量*/
    DECLARE sex TINYINT(2) DEFAULT 0;
    
    #查询结果给变量赋值
    SELECT gender INTO sex FROM gyy_user_t WHERE id=num;
    
    #if 语句
    IF sex=1 THEN
        SET sex=2;
    ELSE
        SET sex=1;
    END IF;
    
    #使用变量
    UPDATE gyy_user_t SET gender = sex WHERE id=num;
    
    #循环
    DECLARE i INT(11) DEFAULT 0;
    lop:LOOP
        SELECT i;
        IF i=5 THEN
            LEAVE lop;#跳出循环
        END IF;
        SET i = i + 1;
    END LOOP lop;
    
    /*查询结果放游标进行遍历*/
    DECLARE idnew INT(11);
    declare done INT(2); 
    DECLARE idList CURSOR FOR (SELECT id FROM gyy_user_t WHERE id IN(10267,10268,10269));
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;#游标中的内容执行完后将done设置为1
    
    OPEN idList;
        lop:LOOP
            #1. 取游标中的值
            FETCH idList INTO idnew;
            #2. 跳出循环条件
            IF done=1 THEN    
                LEAVE lop;
            END IF;
            #3. 执行业务逻辑
            SELECT idnew;
        END LOOP lop;
    CLOSE idList;

END