mysql 存储过程demo

Posted 2021-02-13

从没写过mysql 存储过程，靠着百度和以前写oracle存储过程的经验写了一个，还算顺利，留个例子吧

CREATE DEFINER=`west_brain`@`%` PROCEDURE `man_tree_area`( )
BEGIN
  -- 存储树状结果处理sql变量
    DECLARE
        var_code VARCHAR ( 1000 );
    DECLARE
        var_pcode VARCHAR ( 1000 );
    DECLARE
        var_name VARCHAR ( 1000 );
    DECLARE
        var_count INT;

    -- 存储的一些标记变量    
    DECLARE
        buf_parents VARCHAR ( 1000 ) DEFAULT ‘‘;
    DECLARE
        buf_names VARCHAR ( 1000 ) DEFAULT ‘‘;
    DECLARE
        buf_code VARCHAR ( 100 ) DEFAULT ‘‘;
    DECLARE
        buf_update INT DEFAULT FALSE;
    DECLARE 
      buf_is_leaf INT DEFAULT 0;

    -- 树级别 根为1
    DECLARE 
      buf_tree_level int DEFAULT 0;
    -- 是否叶子节点 0 非 1是
    DECLARE 
      buf_tree_leaf int DEFAULT 1;

    -- 存储表循环游标的变量
    DECLARE
        vcode VARCHAR ( 64 );
    DECLARE
        vparent VARCHAR ( 1000 );

    -- 游标结束的处理变量
    DECLARE
        done INT DEFAULT FALSE;

    -- 定义表循环游标
    DECLARE
        mycursor CURSOR FOR ( SELECT CODE, parent FROM adm_sys_area_info );

    -- 定义游标溢出的处理操作
    DECLARE
        CONTINUE HANDLER FOR NOT FOUND 
        SET done = TRUE;

    -- 打开游标
    OPEN mycursor;

    -- 定义游标循环
    tableloop :
    LOOP
        -- 读取游标的一条数据到变量里
            FETCH mycursor INTO vcode,
            vparent;

        -- 如果上步游标操作没有读取到记录，则done 会被设置为 TRUE，退出 名称为myloop的循环
        IF
            done THEN
                LEAVE tableloop;
        END IF;

        -- 记录当前记录的区域编码
        SET buf_code = vcode; 

        -- 判断自己是否是叶子节点
        SELECT count(*) into var_count from adm_sys_area_info where parent  = vcode;

        if var_count = 0 then
          update adm_sys_area_info set tree_leaf = 1 where code = vcode;
        else
          update adm_sys_area_info set tree_leaf = 0 where code = vcode;
        end if;

        set var_count = 0;

    -- 循环查找自己的父节点
        treeloop :
        LOOP

          -- 判断自己是否存在父节点，用count来判断
            SELECT
                count( * ) INTO var_count 
            FROM
                adm_sys_area_info 
            WHERE
                CODE = vparent;

            IF
                var_count = 0 THEN
                -- 没有上级节点了，则开始处理以前找到的父节点
                IF
                    buf_update THEN-- 更新缓存的数据
                    -- buf_update 为TRUE 则说明找到过父节点

                    -- 下面两个记录处理拼接的字符串末尾多的逗号的问题
                    IF
                        ( length( buf_parents ) > 0 ) THEN

                            SET buf_parents = LEFT ( buf_parents, CHAR_LENGTH( buf_parents ) - 1 );
                    END IF;
                    IF
                        ( length( buf_names ) > 0 ) THEN

                            SET buf_names = LEFT ( buf_names, CHAR_LENGTH( buf_names ) - 1 );
                    END IF;

                    -- 更新当前节点的父信息
                    UPDATE adm_sys_area_info 
                    SET parents = buf_parents,
                    tree_names = buf_names ,tree_level = buf_tree_level 
                    WHERE
                        CODE = buf_code;

                ELSE
                  -- 当前记录是根节点
                    update adm_sys_area_info set tree_level = 1 where code = buf_code;
                END IF;

                -- 清理变量
                SET buf_parents = ‘‘;
                SET buf_names = ‘‘;
                SET vparent = ‘‘;
                SET buf_code = ‘‘;
                SET buf_update = FALSE;
                SET buf_tree_level = 1;

                -- 结束当前记录的处理循环
                LEAVE treeloop;

                ELSE 
                  -- 查找到了父节点
                    SET buf_update = TRUE;
                    -- 查询当前节点的父节点信息
                    SELECT CODE,
                        parent,
                        area_name INTO var_code,
                        var_pcode,
                        var_name 
                    FROM
                        adm_sys_area_info 
                    WHERE
                        CODE = vparent;

                    -- 连接字符串
                    SET buf_parents = CONCAT_WS( ‘,‘, var_code, buf_parents );
                    SET buf_names = CONCAT_WS( ‘,‘, var_name, buf_names );
                    -- 记录当前查找到记录的父节点code
                    SET vparent = var_pcode;
                    SET buf_tree_level = buf_tree_level + 1;

            END IF;

        END LOOP;

    END LOOP;
    CLOSE mycursor;

END