Mysql函数生成查询分表sql

经常给领导查数据，但是数据库不少表是分表的，查询起来粘贴复制很麻烦，这里仅作记录，之前已经介绍过Mysql存储过程的使用，和变量声明，以及分支判断等。

mysql 存储过程简单使用 ：https://www.cnblogs.com/jefferyfeng/p/14479399.html

/**
 * 生成分表查询语句
 * sqls：原始sql，带有占位符
 * tableNums: 分表个数
 * skipType: 跳过分表类型 0.不跳过 1.跳过奇数表 2.跳过偶数表
 * replaceStr: 替换占位符
 *
 * @date 2021-11-08
 * @author fdh
 */
CREATE DEFINER=`root`@`%` FUNCTION `buildSql`(sqls varchar(1000), tableNums int(3), skipType int(1), replaceStr varchar(100)) RETURNS text CHARSET utf8
BEGIN
  set @oriSql = sqls;
    set @oriReplaceStr = replaceStr;
    set @i = 0;
    set @tempSql = '';
    set @replaceSql = '';
    -- 循环开始
    while @i<tableNums DO 
    
        if (skipType = 1 and mod(@i, 2) = 0) then 
            set @replaceSql := replace(@oriSql, @oriReplaceStr, @i);
        elseif (skipType = 2 and mod(@i, 2) = 1) then 
            set @replaceSql := replace(@oriSql, @oriReplaceStr, @i);
        end if;
        
        if (skipType = 0 and @replaceSql = '') then
                set @replaceSql := replace(@oriSql, @oriReplaceStr, @i);
        end if;
        
      if (@tempSql = '' and @replaceSql != '') then 
            set @tempSql := CONCAT(@replaceSql, '\n');
        elseif (@tempSql != '' and @replaceSql != '') then
            set @tempSql := CONCAT(@tempSql, 'union all\n', @replaceSql, '\n');
        end if;
        
        -- 重置
        set @i := @i + 1;
        set @replaceSql := '';
    end while; 
    -- 循环结束
    RETURN @tempSql;
END

---

使用示例：

select buildSql("select DATE_FORMAT(create_time, '%Y-%m') as months, count(1) as counts from crm_clue_call_record*prefix* where create_time > '2021-11-01 00:00:00' and create_time < '2021-11-08 00:00:00' group by DATE_FORMAT(create_time, '%Y-%m')", 32, 2, "*prefix*");