mysql联合都不起作用

Posted 2023-03-24

【中文标题】mysql联合都不起作用

【英文标题】：mysql union all not working

【发布时间】：2014-02-11 21:54:01

【问题描述】：

使用下面的 mysql 代码和 ORDER BY 不起作用。我已经搜索并尝试了各种版本的代码（UNION，UNION ALL，带括号，不带括号，一个 SELECT 包装所有 SELECT UNION ALL 然后对其进行排序） - 没有运气。还有其他建议吗？

        (SELECT FORMAT(lt.`rets_111`, 0) AS 'ListPrice', lt.`rets_128` AS 'MlsNumber', lt.`rets_13` AS 'Address', lt.`rets_2044` AS 'PublicRemarks', lt.`rets_sysid`, @real_estate_type:='res' AS real_estate_type,
    lt.`rets_2362` AS 'OpenHouseDate1', lt.`rets_2364` AS 'OpenHouseStartTime1', lt.`rets_2366` AS 'OpenHouseEndTime1', lt.`rets_2370` AS 'DisplayOpenHouse1',
    lt.`rets_2372` AS 'OpenHouseDate2', lt.`rets_2374` AS 'OpenHouseStartTime2', lt.`rets_2376` AS 'OpenHouseEndTime2', lt.`rets_2380` AS 'DisplayOpenHouse2'
    FROM res_listings AS lt
    WHERE lt.`rets_32` IN ('AGENT1', 'AGENT2') OR lt.`rets_2337` IN ('AGENT1', 'AGENT2') OR lt.`rets_1836` IN ('AGENT1', 'AGENT2'))

    UNION ALL

    (SELECT FORMAT(lt.`rets_111`, 0) AS 'ListPrice', lt.`rets_128` AS 'MlsNumber', lt.`rets_13` AS 'Address', lt.`rets_2044` AS 'PublicRemarks', lt.`rets_sysid`, @real_estate_type:='con' AS real_estate_type,
    lt.`rets_2362` AS 'OpenHouseDate1', lt.`rets_2364` AS 'OpenHouseStartTime1', lt.`rets_2366` AS 'OpenHouseEndTime1', lt.`rets_2370` AS 'DisplayOpenHouse1',
    lt.`rets_2372` AS 'OpenHouseDate2', lt.`rets_2374` AS 'OpenHouseStartTime2', lt.`rets_2376` AS 'OpenHouseEndTime2', lt.`rets_2380` AS 'DisplayOpenHouse2'
    FROM con_listings AS lt
    WHERE lt.`rets_32` IN ('AGENT1', 'AGENT2') OR lt.`rets_2337` IN ('AGENT1', 'AGENT2') OR lt.`rets_1836` IN ('AGENT1', 'AGENT2'))

    UNION ALL

    (SELECT FORMAT(lt.`rets_111`, 0) AS 'ListPrice', lt.`rets_128` AS 'MlsNumber', lt.`rets_13` AS 'Address', lt.`rets_2044` AS 'PublicRemarks', lt.`rets_sysid`, @real_estate_type:='mul' AS real_estate_type,
    lt.`rets_2362` AS 'OpenHouseDate1', lt.`rets_2364` AS 'OpenHouseStartTime1', lt.`rets_2366` AS 'OpenHouseEndTime1', lt.`rets_2370` AS 'DisplayOpenHouse1',
    lt.`rets_2372` AS 'OpenHouseDate2', lt.`rets_2374` AS 'OpenHouseStartTime2', lt.`rets_2376` AS 'OpenHouseEndTime2', lt.`rets_2380` AS 'DisplayOpenHouse2'
    FROM mul_listings AS lt
    WHERE lt.`rets_32` IN ('AGENT1', 'AGENT2') OR lt.`rets_2337` IN ('AGENT1', 'AGENT2') OR lt.`rets_1836` IN ('AGENT1', 'AGENT2'))

    UNION ALL

    (SELECT FORMAT(lt.`rets_111`, 0) AS 'ListPrice', lt.`rets_128` AS 'MlsNumber', lt.`rets_13` AS 'Address', lt.`rets_2044` AS 'PublicRemarks', lt.`rets_sysid`, @real_estate_type:='rnt' AS real_estate_type,
    lt.`rets_2362` AS 'OpenHouseDate1', lt.`rets_2364` AS 'OpenHouseStartTime1', lt.`rets_2366` AS 'OpenHouseEndTime1', lt.`rets_2370` AS 'DisplayOpenHouse1',
    lt.`rets_2372` AS 'OpenHouseDate2', lt.`rets_2374` AS 'OpenHouseStartTime2', lt.`rets_2376` AS 'OpenHouseEndTime2', lt.`rets_2380` AS 'DisplayOpenHouse2'
    FROM rnt_listings AS lt
    WHERE lt.`rets_32` IN ('AGENT1', 'AGENT2') OR lt.`rets_2337` IN ('AGENT1', 'AGENT2') OR lt.`rets_1836` IN ('AGENT1', 'AGENT2'))

    UNION ALL

    (SELECT FORMAT(lt.`rets_111`, 0) AS 'ListPrice', lt.`rets_128` AS 'MlsNumber', lt.`rets_13` AS 'Address', lt.`rets_2044` AS 'PublicRemarks', lt.`rets_sysid`, @real_estate_type:='ici' AS real_estate_type,
    lt.`rets_2362` AS 'OpenHouseDate1', lt.`rets_2364` AS 'OpenHouseStartTime1', lt.`rets_2366` AS 'OpenHouseEndTime1', lt.`rets_2370` AS 'DisplayOpenHouse1',
    lt.`rets_2372` AS 'OpenHouseDate2', lt.`rets_2374` AS 'OpenHouseStartTime2', lt.`rets_2376` AS 'OpenHouseEndTime2', lt.`rets_2380` AS 'DisplayOpenHouse2'
    FROM ici_listings AS lt
    WHERE lt.`rets_32` IN ('AGENT1', 'AGENT2') OR lt.`rets_2337` IN ('AGENT1', 'AGENT2') OR lt.`rets_1836` IN ('AGENT1', 'AGENT2'))

    UNION ALL

    (SELECT FORMAT(lt.`rets_111`, 0) AS 'ListPrice', lt.`rets_128` AS 'MlsNumber', lt.`rets_13` AS 'Address', lt.`rets_2044` AS 'PublicRemarks', lt.`rets_sysid`, @real_estate_type:='far' AS real_estate_type,
    lt.`rets_2362` AS 'OpenHouseDate1', lt.`rets_2364` AS 'OpenHouseStartTime1', lt.`rets_2366` AS 'OpenHouseEndTime1', lt.`rets_2370` AS 'DisplayOpenHouse1',
    lt.`rets_2372` AS 'OpenHouseDate2', lt.`rets_2374` AS 'OpenHouseStartTime2', lt.`rets_2376` AS 'OpenHouseEndTime2', lt.`rets_2380` AS 'DisplayOpenHouse2'
    FROM far_listings AS lt
    WHERE lt.`rets_32` IN ('AGENT1', 'AGENT2') OR lt.`rets_2337` IN ('AGENT1', 'AGENT2') OR lt.`rets_1836` IN ('AGENT1', 'AGENT2'))

    UNION ALL

    (SELECT FORMAT(lt.`rets_111`, 0) AS 'ListPrice', lt.`rets_128` AS 'MlsNumber', lt.`rets_13` AS 'Address', lt.`rets_2044` AS 'PublicRemarks', lt.`rets_sysid`, @real_estate_type:='lot' AS real_estate_type,
    lt.`rets_2362` AS 'OpenHouseDate1', lt.`rets_2364` AS 'OpenHouseStartTime1', lt.`rets_2366` AS 'OpenHouseEndTime1', lt.`rets_2370` AS 'DisplayOpenHouse1',
    lt.`rets_2372` AS 'OpenHouseDate2', lt.`rets_2374` AS 'OpenHouseStartTime2', lt.`rets_2376` AS 'OpenHouseEndTime2', lt.`rets_2380` AS 'DisplayOpenHouse2'
    FROM lot_listings AS lt
    WHERE lt.`rets_32` IN ('AGENT1', 'AGENT2') OR lt.`rets_2337` IN ('AGENT1', 'AGENT2') OR lt.`rets_1836` IN ('AGENT1', 'AGENT2'))

    ORDER BY 'ListPrice' DESC

【参考方案1】：

这是你的order by：

ORDER BY 'ListPrice' DESC

它是按常量字符串排序的。试试这个：

ORDER BY ListPrice DESC

而且，在未来，字符串和日期常量值只能使用单引号。永远不会，永远不会用于数据库中事物的名称。

【讨论】：

谢谢！抱歉，如果这是一个愚蠢的问题，但是您在代码中指的是关于单引号以及应如何使用它们的代码？

@user3299111 。 . .单引号是出现在ListPrice 周围的'。这会导致列名被视为常量值，这对于排序没有用处。

所以如果名称中没有空格，我不需要任何形式的引号？

如果名称不是 SQL 中的保留字（如“like”、“in”、“select”、“from”、“between”等）并且您只使用字母数字字符、数字和下划线，则不需要引用变量名。

如果你不介意还有一个问题，我使用的反引号呢？在使用保留字的情况下，作为预防措施和习惯是必要的吗？