具有多个 UNION clouse 的复杂 mysql 查询末尾的 ORDER BY FIELD 子句

Question

我已经仔细阅读了这个： How to use ORDER BY inside UNION

尽管如此，ORDER BY 子句不适用于这个复杂的查询：

SELECT *, 'tbl' as src   FROM
(

SELECT name3, prec3, name6, prec6  
FROM `prec3_2015` p3
    JOIN `prec6_2015` p6  
    ON p3.m_d_t = p6.m_d_t AND name3 = name6
WHERE prec3 != '-' AND p3.time = 12 and p3.date = 24 and p3.month = 1 AND prec6 != '999' 
    AND (name6 REGEXP 'Shabla|Kaliakra|Varna' )      
    GROUP BY name3

UNION

SELECT name3, prec3, name6, prec6  
FROM `prec3_2015` p3
    JOIN `prec6_2015` p6
    ON p3.m_d_t = p6.m_d_t AND name3 = name6
WHERE prec3 != '-' AND p3.time = 12 and p3.date = 24 and p3.month = 1 AND prec6 = '999' 
    AND (name3 REGEXP 'Shabla|Kaliakra|Varna')      
    GROUP BY name3

UNION

    SELECT name3, prec3, name6, prec6 
FROM `prec3_2015` p3
    JOIN `prec6_2015` p6
    ON p3.m_d_t = p6.m_d_t AND name3 = name6
WHERE prec3 = '-' AND p3.time = 12 and p3.date = 24 and p3.month = 1 AND prec6 != '999' 
AND (name6 REGEXP 'Shabla|Kaliakra|Varna')      
   GROUP BY name6
) tbl


UNION


SELECT *, 'tbl' as src   FROM
(

SELECT name3, prec3, name6, prec6    
FROM `prec3_2015` p3
    JOIN `prec6_2015` p6
    ON p3.m_d_t = p6.m_d_t AND name3 = name6
WHERE prec3 != '-' AND p3.time = 12 and p3.date = 24 and p3.month = 1 AND prec6 != '999' 
    AND (name6 REGEXP 'N.selo|Vidin|Vratca')   GROUP BY name3

UNION

SELECT name3, prec3, name6, prec6  
FROM `prec3_2015` p3
    JOIN `prec6_2015` p6
    ON p3.m_d_t = p6.m_d_t AND name3 = name6
WHERE prec3 != '-' AND p3.time = 12 and p3.date = 24 and p3.month = 1 AND prec6 = '999' 
    AND (name3 REGEXP 'N.selo|Vidin|Vratca')      
GROUP BY name6

UNION

SELECT name3, prec3, name6, prec6   
FROM `prec3_2015` p3
    JOIN `prec6_2015` p6
    ON p3.m_d_t = p6.m_d_t AND name3 = name6
WHERE prec3 = '-' AND p3.time = 12 and p3.date = 24 and p3.month = 1 AND prec6 != '999' 
AND (name6 REGEXP 'N.selo|Vidin|Vratca')      
GROUP BY name6
) tbl

ORDER BY FIELD (src, 'Shabla|Kaliakra|Varna|N.selo|Vidin|Vratca')

这两个表几乎相同，有 7 列 - id、month、date、time、m_d_t、name3、prec3 或 name6、prec6第二张桌子。我不明白如何以查询末尾描述的方式订购结果？ 提前谢谢你！

Answer 1

ORDER BY FIELD 应该是，

ORDER BY FIELD (src, 'Shabla', 'Kaliakra', 'Varna', 'N.selo', 'Vidin', 'Vratca')

您应该提供由, 分隔的值，而不是像带有| 的正则表达式

参考：ORDER BY FIELD in specific order

Answer 2

试试这样的：

SELECT name3, prec3, name6, prec6, name6 AS src  
...

UNION

SELECT name3, prec3, name6, prec6, name3 AS src  
...

...

UNION

SELECT name3, prec3, name6, prec6, name6 AS src  
...

ORDER BY FIELD (src, 'Shabla', 'Kaliakra', 'Varna', 'N.selo', 'Vidin', 'Vratca')

删除外部查询。

在每个查询的SELECT 子句中添加一个新表达式X AS src，其中X 是1、2、3 等等，每个查询都有一个不同的值。

最后一个查询之后的ORDER BY 子句适用于UNION 级别；没有必要使用括号。但是，如果您想让它更清楚，您可以将每个查询括在括号中，并将 UNIONs 和 ORDER BY 留在括号外。

您将获得第一个 SELECT 返回的行，然后是第二个 SELECT 返回的行，依此类推。但是，每个选择返回的行没有特定的顺序（这就是您需要它们的样子）。