Question

如果选择表A UNION表B：

，我如何通过基于id的结果来查询组以捕获“yy”

表A：

id|field1|field2|field3

1 | xx   | yy   | xx

表B：

id|field1|field2|field3

1 | yy   | xx   | xx

我想要的结果：

id|field1|field2|field3

1 | yy   | yy   | xx

Answer 1

您可以使用自然连接进行此操作并像这样查询

select * from table1 
inner join table2

Answer 2

你可以从工会做最小/最大：

select id, min(field1), min(field2), min(field3)
from (
  select id, field1, field2, field3
  from table_A
  union
  select id, field1, field2, field3
  from table_B
) as q

Answer 3

您似乎想要：

select id,
       (case when sum(field1 = 'yy') > 0 then 'yy' else max(field1) end) as field1,
       (case when sum(field2 = 'yy') > 0 then 'yy' else max(field2) end) as field2,
       (case when sum(field3 = 'yy') > 0 then 'yy' else max(field3) end) as field1,
from ((select id, field1, field2, field3
       from table_A
      ) union
      (select id, field1, field2, field3
       from table_B
      ) 
     ) ab
group by id;

Answer 4

我认为这不是那么复杂，所以你需要使用MIN / MAX。你可以在下面试试 -

SELECT A.id, B.field1, A.field2, A.field3
FROM TABLE_A
INNER JOIN TABLE_B
ON A.id = B.id

Union groupby子句具有特定值

4 个答案: