在子子查询中访问一个字段SQL

Question

我有一个相当复杂的查询，我正在处理多个嵌套的查询层。查询的一个要求是我从主查询中的子查询的子查询中访问一个字段。但是，由于中间查询中的聚合，我无法在该查询中包含该字段。

例如。

select a, d.x, f.v? 
from b 
    join (select a, max(z), min(z), Count(y) as x 
     from c 
      join (select a, Count(t) as v 
       from e 
       ) f 
      on f.a = c.a 
      Group By a 
      Having min(z) <> max(z) 
     ) d 
    on d.a = b.a 

这可能吗？

Answer 1

编号

试试这个。基本上，获取你需要的属性，当你上升阶层（可能需要重命名），然后使用它们。

Select a, d.fa From b 
join (select a,f.a fa from c 
join (select a from e) f on f.a = c.a 
) d on d.a = b.a 

我还没有测试表..如果您看到更多问题，请将它们发布到此处。

*基于更新的问题*

即使在这里编辑，逻辑是一样的，你必须要么使用...

select a, d.x, d.v? 
from b 
    join (select a, f.v, max(z), min(z), Count(y) as x 
     from c 
      join (select a, v 
       from e 
       ) f 
      on f.a = c.a 
      Group By a, f.v 
      Having min(z) <> max(z) 
     ) d 
    on d.a = b.a 

或者，如果你的数据库支持标量子查询，你可以得到在最后的外部查询使用..

select a, d.x, (select v from e where e.a = b.a) f_v 
from b 
    join (select a, max(z), min(z), Count(y) as x 
     from c 
      join (select a, v 
       from e 
       ) f 
      on f.a = c.a 
      Group By a 
      Having min(z) <> max(z) 
     ) d 
    on d.a = b.a 

Answer 2

它可能是更直接的，如果你只是把表y有关（在这种情况下，E）回到FROM子句

SELECT a, 
     d.x, 
     e.v 
FROM b 
     JOIN (SELECT a, 
          MAX(z), 
          MIN(z), 
          COUNT(y) AS x 
        FROM c 
          JOIN (SELECT a 
           FROM e) f 
          ON f.a = c.a 
        GROUP BY a 
        HAVING MIN(z) <> MAX(z)) d 
     ON d.a = b.a 
     JOIN (SELECT a, Count(t) as v 
      FROM e 
      GROUP BY A) e 
     ON e.a = d.a