加入三個表與SQL Server數據庫計數

我有這三個表（Soknad，預測和DID）：加入三個表與SQL Server數據庫計數

表Soknad有列：S_ID（鍵），S_REFNR

表Prognose有列： P_ID（鍵），P_S_ID

表的所作所爲列：D_ID（鍵），D_S_ID，Did_Something

Prognose.P_S_ID是外鍵Soknad.S_ID。 Did.D_S_ID是Soknad.S_ID的外鍵。

的表是這樣的：

SOKNAD

S_ID | S_REFNR | 
    1 | abc  | 
    2 | cbc  | 
    3 | sdf  |

PROGNOSE

P_ID | P_S_ID | 
    10 | 1  | 
    11 | 2  |

DID

D_ID | D_S_ID | D_Did_Something | 
    100 | 1  | 1    | 
    101 | 1  | 1    | 
    102 | 1  | 0    | 
    103 | 2  | 1    | 
    104 | 2  | 1    |

我想加入這些表（如查看或選擇聲明）。在Did表中，應該返回Did_Something列的計數，以及值爲1（1）的同一列的計數。結果應該是：

S_ID | S_REFNR | P_ID | Count_D_Did_Something | Count_D_Did_Something_Is_One | 
1 | abc  | 10 | 3      | 2       | 
2 | cbc  | 11 | 2      | 2       | 
3 | sdf  |  |      |        |

任何幫助將不勝感激！

來源

2013-11-20 Batar

哪個平臺？（或者你使用非mysql）？ – Hogan

在這裏你去：

select s.s_id, 
     p.p_id, 
     count(d.Did_Something) as Count_D_Did_Something, -- nulls won't be counted 
     sum(CASE WHEN d.Did_Something = 1 THEN 1 ELSE 0 END) as Count_D_Did_Something_is_one 
from Soknad as s 
     left join Prognose as p on p.P_S_ID = s.s_id 
     left join Did as d on d.D_S_ID = s.s_id

來源

2013-11-20 18:43:58 Hogan

謝謝，我在最後加上了s.s_id組，p.p_id，然後工作。 – Batar

我相信你想要做的就是加入兩個表，並把行數與左表分別放在每個表的不同列中。

這將實現這一目標。

select t1.id, count(t2.id) t2_count , count(t3.id) t3_count 
from table1 as t1 
     left outer join table2 as t2 on t2.table1_id = t1.id 
     left outer join table3 as t3 on t3.table1_id = t1.id 
group by t1.id;

爲了實現基於標準從外連接表的一個你想要的數量，你可以做，這樣一來，使用派生的表...

select t1.id, count(t2.id) t2_count, count(tt2.mCount) Did_SomethingCount, count(t3.id) t3_count 
from table1 as t1 
     left outer join table2 as t2 on t2.table1_id = t1.id 
     left outer join (select count(*), table1_id mCount from table2 where Did_Something = 1 group by table1_id) as tt2 on tt2.table1_id = t1.id 
     left outer join table3 as t3 on t3.table1_id = t1.id 
group by t1.id;

來源

2013-11-20 18:37:30

這應該只是給你需要的結果。請注意，我只是簡單總結一下當你想要數值爲1時，

SELECT S.S_ID, S.REFNR, P.P_ID, COUNT(D.D_DID_SOMETHING) AS COUNT_D_DID_SOMETHING, 
SUM(D_DID_SOMETHING) AS COUNT_D_DID_SOMETHING_IS_ONE 
FROM SOKNAD AS S 
INNER JOIN PROGNOSE AS P 
ON P.P_S_ID = S.S_ID 
INNER JOIN DID AS D 
ON D.D_S_ID = S.S_ID 
GROUP BY S.S_ID, S.REFNR, P.P_ID

來源

2013-11-20 18:57:20 Santhosh

加入三個表與SQL Server數據庫計數

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