多个 INNER JOIN 上的 SQL SUM

Question

我正在尝试使用连接通过多个表获取特定字段的总和。 当我尝试将这些值放在一起时，我弄错了 SUM。

我有表状态

| STATE |   MONTH | ID | TOTAL |
--------------------------------
|    FL |    July |  1 | 10000 |
|    CA |   April | 32 |  2000 |

我有另一张表余额为

| STATE |  Balance|
-------------------
|    FL |      100|
|    FL |      200|
|    CA |      300|
|    CA |      200|
|    CA |      100|

我还有一张桌子贷款

| STATE |     Loan|
-------------------
|    FL |      500|
|    FL |      600|
|    CA |      700|
|    CA |      100|
|    CA |      200|

作为查询的结果，我想要的是，

| STATE |     Loan| Balance|
----------------------------
|    FL |     1100|     300|
|    CA |     1000|     600|

当我尝试使用以下查询时，我正确地获得了带有状态的贷款总和，

SELECT 
  S.STATE, 
  SUM(L.Loan) 
FROM State AS S
  INNER JOIN Loan AS L ON L.STATE = S.STATE
GROUP BY
 S.STATE

我得到以下结果，

| STATE |      Loan|
--------------------
|    FL |      1100|
|    CA |      1000|

同样，我可以从余额表中得到总和。 我想要实现的是使用单个事务从两个表中获取总和。

虽然，我能够得到想要的值，但如果我做这样的事情，

SELECT
  STATE AS STATE
  SUM(DataSetB.Balance) AS Balance
FROM
    (
    SELECT 
      STATE AS STATE,
      B.Balance AS Balance
    FROM
        (
        SELECT 
          S.STATE AS STATE, 
          SUM(L.Loan) AS Loan,
        FROM State AS S
          INNER JOIN Loan AS L ON L.STATE = S.STATE
        GROUP BY S.STATE
        )
        AS DataSetL
     INNER JOIN Balance AS B ON B.STATE = DataSetL.STATE
     GROUP BY
       DataSetL.STATE, B.Balance
     ) AS DataSetB
GROUP BY 
  DataSetB.STATE

然而，这在我拥有的大型数据集上不太可行。 我试过了，

SELECT 
  S.STATE AS STATE, 
  SUM(L.Loan) AS Loan,
  SUM(B.Balance) AS Balance
FROM State AS S
  INNER JOIN Loan AS L ON L.STATE = S.STATE
  INNER JOIN Balance AS B ON B.STATE = S.STATE
GROUP BY 
  S.STATE

但这给了我实际值的倍数。 它实际上是子表中存在的行数的倍数。

我不是要求一个确切的解决方案，但任何类型的指针都会很好。

Answer 1

你可以试试这个，使用UNION ALL结合Balance和Loan表并使用一点技巧，

• Balance填写Loan栏设置 0
• Loan填写Balance列设置 0

然后JOIN与State做SUM

create table State(
  STATE varchar(50)
);



insert into State values ('FL'); 
insert into State values ('CA'); 
create table Balance(
  STATE varchar(50),
  Balance int
);



insert into Balance values ('FL',100);
insert into Balance values ('FL',200);
insert into Balance values ('CA',300);
insert into Balance values ('CA',200);
insert into Balance values ('CA',100);

create table Loan(
  STATE varchar(50),
  loan int
);

insert into loan values ( 'FL',500);
insert into loan values ( 'FL',600);
insert into loan values ( 'CA',700);
insert into loan values ( 'CA',100);
insert into loan values ( 'CA',200);

查询 1 ：

SELECT s.STATE,SUM(t1.Loan) as 'Loan',SUM(t1.Balance) as 'Balance'
FROM 
(
  SELECT STATE,0 AS Loan,Balance  
  FROM Balance 
  UNION ALL
  SELECT STATE,Loan,0   
  FROM Loan 
) t1
INNER JOIN State s on s.STATE = t1.STATE
GROUP BY s.STATE

结果：

| STATE | Loan | Balance |
|-------|------|---------|
|    CA | 1000 |     600 |
|    FL | 1100 |     300 |

Answer 2

在单独的子查询中对每个表进行聚合，然后加入：

SELECT 
  S.STATE AS STATE, 
  L.Loan,
  B.Balance
FROM State AS S
  LEFT JOIN (select state, sum(loan) as Loan
              from loan
              group by state) AS L ON L.STATE = S.STATE
  LEFT JOIN (select state, sum(Balance) as balance
              from balance
              group by state) AS B ON B.STATE = S.STATE

（左连接，以防一个状态没有贷款或余额行。）

Answer 3

尝试这个：

SELECT S.STATE, L.Loan as TotalLoan, B.Balance as TotalBalance
FROM State AS S
LEFT JOIN (select STATE, sum(Loan) as Loan
           from Loan
           group by STATE) AS L
ON L.STATE = S.STATE

LEFT JOIN (select STATE, sum(Balance) as Balance
           from Balance
           group by STATE) AS B
ON B.STATE = S.STATE

结果是：

| STATE |TotalLoan|TotalBalance|
----------------------------
|    FL |   1100  |     300    |
|    CA |   1000  |     600    |

Answer 4

你可以试试这个：

Select S.State, B.Balance,L.Loan from State S 
inner join (select state, sum(loan) as Loan from Loan group by state) L
inner join (select state, sum(balance) as Balance from Balance group by state) B
on L.state=S.state and B.State=S.State;

Answer 5

使用子查询：首先连接贷款和余额表，然后将状态表与派生表结果连接起来

SELECT 
  S.STATE AS STATE, Loan,Balance
FROM State AS S inner join
 (select L.state,sum(loan) as loan, sum(balance) as balance
 from Loan AS L INNER JOIN Balance AS B ON B.STATE = S.STATE
 GROUP BY L.STATE)X on s.state=x.state

Answer 6

我建议使用公用表表达式，因为它读起来很“干净”。

尝试以下操作：

WITH CTE_TotalLoan AS (
  SELECT
    State,
    SUM(Loan) AS TotalLoan
  FROM Loan
  GROUP BY State
),

CTE_TotalBalance AS (
  SELECT
    State,
    SUM(Balance) AS TotalBalance
  FROM Balance
  GROUP BY State
)

SELECT 
  S.State,
  TotalLoan,
  TotalBalance
FROM State AS S
INNER JOIN CTE_TotalLoan AS L ON L.STATE = S.STATE
INNER JOIN CTE_TotalBalance AS B ON B.STATE = S.STATE

请参阅工作 SQL Fiddle 。

Answer 7

尝试这个：

Create Table #Loan([State] Varchar(10),Loan Bigint)
Create Table #Balance([State] Varchar(10),Balance Bigint)

Insert Into #Loan
Select 'FL',500 Union All
Select 'FL',600 Union All
Select 'CA',700 Union All
Select 'CA',100 Union All
Select 'CA',200

Insert Into #Balance
Select 'FL',100 Union All
Select 'FL',200 Union All
Select 'CA',300 Union All
Select 'CA',200 Union All
Select 'CA',100 

;with cteLoan
AS(
    Select ROW_NUMBER() Over(Partition by State order by State) As Rn, * from #Loan
)
,
cteBalance
AS(
    Select ROW_NUMBER() Over(Partition by State order by State) As Rn, * from #Balance
)

Select DISTINCT ISNULL(l.State,b.State) as State
,SUM(ISNULL(Loan,0)) As Loan
,SUM(ISNULL(Balance,0)) As Balance
from cteLoan l
FULL OUTER JOIN cteBalance b
on l.State=b.State and l.rn=b.rn
Group by ISNULL(l.State,b.State)

Drop Table #Loan
Drop Table #Balance

Answer 8

您也可以使用APPLY ：

SELECT s.*, l.loan, b.balance 
FROM State s OUTER APPLY
     (SELECT SUM(l.loan) loan
      FROM loan l
      WHERE l.state = s.state
     ) l OUTER APPLY 
     (SELECT SUM(b.balance) balance 
      FROM balance b
      WHERE b.state = s.state
     ) b;