Question

这是子查询，可以很好地处理所需的结果，现在我正在为相同的结果编写存储过程。

我想在存储过程逻辑中用作

声明变量
设置它们
用于查询

查询：

SELECT payloadstr,
       starttime
FROM   pa
WHERE  conid IN (SELECT conid
                 FROM   con
                 WHERE  lognid IN (SELECT id
                                   FROM   log
                                   WHERE  phyid IN (SELECT id
                                                    FROM   phyid
                                                    WHERE  mac = 9729)));

Answer 1

这只是代码的建议（特殊问题的答案已在P.Salmon的问题注释中）

而不是嵌套IN（subselect）的集合您可以使用一些内部联接

select pa.str, pa.time 
from pa 
INNER JOIN con ON con.lognid = pa.conid 
INNER JOIN log ON con.lognid = log.id 
INNER JOIN phyid ON log.phyid = phyid.id AND  mac =9729

Answer 2

尝试一下：

BEGIN
    SET @macid = 9729; -- Take input from stored procedure

    SET @phyid_id = (SELECT GROUP_CONCAT(`id`) FROM `phyid` WHERE `mac` = @macid);
    SET @log_id = (SELECT GROUP_CONCAT(`id`) FROM `log` WHERE `phyid` IN(@phyid_id));
    SET @con_conid = (SELECT `conid` FROM `con` WHERE `lognid` IN(@log_id));

    SELECT `str`, `time` FROM `pa` WHERE `conid` IN(@con_conid);
END

MySQL将变量值添加到存储过程中的结果集中而不是子查询

2 个答案: