Question

我想要最低价格用于目的 - 物品和最高价格对于目的-B项目，而且我按区域对项目进行分组。

SELECT ZONE, MIN_PRICE, MAX_PRICE --,LEFT_ZONE
  FROM 
  (SELECT MIN(PRICE) AS MIN_PRICE , ZONE  AS LEFT_ZONE
    FROM MYTABLE 
    WHERE PURPOSE = 'A'
      AND SOMETHING = 'SOMEVALUE'
    GROUP BY ZONE 
   )
    FULL OUTER JOIN 
  (SELECT MAX(PRICE) AS MAX_PRICE, ZONE_CD  
    FROM MYTABLE 
    WHERE PURPOSE = 'B'
      AND SOMETHING = 'SOMEVALUE'
    GROUP BY ZONE 
   )
  ON LEFT_ZONE = ZONE

此查询提供了我想要的输出，但我不喜欢它有两个原因：

1）我想要

FROM MYTABLE 
WHERE SOMETHING = 'SOMEVALUE'

只能被召唤一次。

2）当行来自右表时，我得到ZONE null 在我的完全外部联接。

我怎样才能解决这些问题。

我的查询中是否还有其他问题？

Answer 1

您是否尝试使用CASE表达式来实现此目的：

select zone,
  min(case when PURPOSE = 'A' then price end) min_price,
  max(case when PURPOSE = 'B' then price end) max_price
from MYTABLE 
where SOMETHING = 'SOMEVALUE'
group by zone

Answer 2

试试这个：

  SELECT 
    ZONE, 
    SUM (CASE WHEN PURPOSE = 'A' THEN MIN(PRICE) ELSE 0 END) AS MIN_PRICE,
    SUM (CASE WHEN PURPOSE = 'B' THEN MAX(PRICE) ELSE 0 END) AS MAX_PRICE
  FROM 
    MYTABLE 
  WHERE 
    SOMETHING = 'SOMEVALUE'
  GROUP BY 
    ZONE

或

的任何小变化

如何避免SQL中的子查询重复？

2 个答案: