Question

我有两个表，例如

收入（点，日期，公司）
结果（指向，日期，结束）

其中 point 和 date 是主键。
我需要在任何给定日期找出总收入inc和结果out。我的回答

WITH all_date AS
(SELECT point, date FROM income
UNION
SELECT point, date FROM outcome)
SELECT a.point, a.date, SUM(inc), SUM(out)
FROM all_date a LEFT JOIN income i ON i.point=a.point AND i.date=d.date
                LEFT JOIN outcome o ON o.point=a.point AND o.date=a.date
GROUP BY a.point, a.date

但是我得错了结果。因为all_date LEFT JOIN income尝试与LEFT JOIN进行outcome重复income中的某些行，因此会弄乱最终的SUM。

基本上我想LEFT JOIN第三个表格outcome all_date 而不是 all_date LEFT JOIN income。有关进一步说明，请参阅http://www.sql-ex.ru/learn_exercises.php的第30号课程

Answer 1

为什么不先加入呢？

甚至更好，只需做一个完整的外部联接：

Select coalesce(o.point, i.point) point,
   coalesce(o.Date, i.date) date
From income i full join outcome o
  on o.point=i.point 
     and o.date=i.date
group by coalesce(o.point, i.point),
     coalesce(o.Date, i.date)

并且，由于您实际上并未使用任何聚合函数，因此也可以使用distinct：

Select distinct
   coalesce(o.point, i.point) point,
   coalesce(o.Date, i.date) date
From income i full join outcome o
  on o.point=i.point 
     and o.date=i.date

道歉，我不是MySQL人，也没有意识到MySQL没有Full Join语法。但有一个解决方法。请看以下链接：

Full Join in MYSQL

基本上你需要一个联盟，（接近你正在做的事情，实际上）

select point, date 
from income i
 left join outcome o 
    on o.point=i.point 
      and o.date=i.date  
  UNION                 -- <-- leave out the ALL to eliminate duplicates
select point, date 
from outcome o
 right join income i 
    on i.point=o.point 
      and i.date=o.date

Answer 2

我不知道在这里使用表表达式的目的是什么，你可以在这里使用一个连接来获得结果：

SELECT i.point, i.date, SUM(inc), SUM(out)
FROM  income i 
LEFT JOIN outcome o   
ON o.point=i.point AND o.date=i.date
GROUP BY i.point, i.date

Answer 3

MS-SQL sp解决您的问题：

CREATE PROCEDURE dototals
@date DATETIME
AS
BEGIN

SELECT point,SUM(ISNULL(inc,0)) as inc into #tmp_i FROM Income WHERE date =@date  GROUP BY point

SELECT point,SUM(ISNULL(out,0)) as out into #tmp_d FROM Outcome WHERE date =@date  GROUP BY point

SELECT DISTINCT point into #tmp_p FROM 
(SELECT point FROM #tmp_i
UNION ALL
SELECT point FROM #tmp_o)

SELECT @date as date, t1.point as point, t2.out as outcome,t3.inc as income 
FROM #tmp_p as t1
LEFT JOIN #tmp_o as t2 on t1.point=t2.point
LEFT JOIN #tmp_i as t3 on t1.point=t3.point
END

Answer 4

这是我在MSSQL中的最终解决方案。但我希望COALESCE使用FULL JOIN效果最佳。

    WITH all_date AS
    (SELECT point, date FROM income
    UNION
    SELECT point, date FROM outcome)

    SELECT a.point, a.date,
    (SELECT SUM(o.out) FROM outcome o WHERE o.point=a.point AND o.date=a.date) AS outcome,
    (SELECT SUM(i.inc) FROM income i WHERE i.point=a.point AND i.date=a.date) AS income

    FROM all_date a

LEFT JOIN 3rd Table到原始表而不是结果表

4 个答案: