从 sql 服务器中的多个 table 获取数据

Question

我有 3 个 table，我想使用连接从那些 table 中获取数据。这是我的 table 结构和这 3 table 中的数据。

我正在使用 MS Sql 服务器。

Year    Month      TotalNewCaseAmount   TotalNewCaseCount   TotalClosingAmount   TotalReturnCount   TotalClosingAmount   TotalReturnCount  

2016    Januray     146825.91           1973                54774.41                147                 299.35              41

2016    Fabuary     129453.30           5384                46443.99                7                   7568.21             123

2016    March       21412.07            3198                Null                    Null                78.83               73

2016    April       0.00                5                   Null                    Null                Null                NULL

我不知道哪个连接会得到这个结果，我试过 CROSS 连接，但它会给我 36 行。

Answer 1

这样试试，

select
t1.*,
t2.TotalClosingAmount,
t2.TotalClosingCount,
t3.TotalRetrunAmount,
t3.TotalReturnCount
from 
Table1 t1
left join 
Table2 t2 on t1.year=t2.year
and t1.month=t2.month
left join 
Table3 t3 on t1.year=t3.year
and t1.month=t3.month

Answer 2

请试试这个

    select year,month, totalnewcasesamount,totalnewcasescount,
    totalclosingamount,totalclosingcount,totlareturnamopunt,totalreturncount   

    from table1 full outer join 
    table2
    on table1.year=table2.year
    and table1.month=table2.month    
    full outer join table3
    on table1.year=table3.year
    and table1.month=table3.month
    where table1.year is not null
    and table1.month is not nulll

Answer 3

这样就可以了：

;WITH Table1 AS (
SELECT *
FROM (VALUES
(2016, 'Januray',  146825.91, 1973),
(2016, 'Fabuary',  129453.30, 5384),
(2016, 'March',    21412.07, 3198),
(2016, 'April',    0.00, 5)
) as t ([Year], [Month], TotalNewCaseAmount, TotalNewCaseCount)
), Table2 AS (
SELECT *
FROM (VALUES
(2016, 'Januray', 54774.41, 147),
(2016, 'Fabuary', 46443.99, 7)
) as t ([Year], [Month], TotalClosingAmount, TotalClosingCount)
), Table3 AS (
SELECT *
FROM (VALUES
(2016, 'Januray', 299.35, 41),
(2016, 'Fabuary', 7568.21, 123),
(2016, 'March', 78.83, 73)
) as t ([Year], [Month], TotalReturnAmount, TotalReturnCount)
)

SELECT  t1.[Year],
        t1.[Month],
        t1.TotalNewCaseAmount,
        t1.TotalNewCaseCount,
        t2.TotalClosingAmount,
        t2.TotalClosingCount,
        t3.TotalReturnAmount,
        t3.TotalReturnCount  
FROM table1 t1
LEFT JOIN table2 t2 
    ON t1.[Year] = t2.[Year] AND t1.[Month] = t2.[Month]
LEFT JOIN table3 t3
    ON t1.[Year] = t3.[Year] AND t1.[Month] = t3.[Month]

输出：

Year    Month   TotalNewCaseAmount  TotalNewCaseCount   TotalClosingAmount  TotalClosingCount   TotalReturnAmount   TotalReturnCount
2016    Januray 146825.91           1973                54774.41            147                 299.35              41
2016    Fabuary 129453.30           5384                46443.99            7                   7568.21             123
2016    March   21412.07            3198                NULL                NULL                78.83               73
2016    April   0.00                5                   NULL                NULL                NULL                NULL

只需将 table1、table2 和 table3 更改为您的实际 table 名称即可。

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