Question

我是sql的新手。我有这些表：

表格个人：

IndividualId  IndividualName  
Ind1          Mark
Ind2          Paul
ind3          Spencer
ind4          Mike
ind5          Hilary

表代理：

AgentId     IndId(foreignKey)
Agent1      ind1
Agent1      ind2
Agent2      ind1
Agent3      ind4

交易表（交易可以通过代理商或个人自己进行）：

TranId   IndId(foreignKey/Never Null)  AgentId(foreignKey)  TranAmount
Tran1    ind1                          Agent1               $100
Tran2    ind1                          NULL                 $500
tran3    ind3                          NULL                 $200
tran4    ind4                          Agent3               $50
tran5    ind4                          NULL                 $30

结果应该是:(如果交易与代理关联，则显示在同一行，否则显示在单独的行上）

IndividualId  IndividualName  AgentId    TranId    TranAmount
Ind1          Mark            Agent1     Tran1     $100
Ind1          Mark            Agent2     NULL      NULL
Ind1          Mark            NULL       Tran2     $500
Ind2          Paul            Agent1     NULL      NULL
Ind3          Spencer         NULL       Tran3     $200
ind4          Mike            Agent3     tran4     $50
ind4          Mike            NULL       tran5     $30
ind5          Hilary          NULL       NULL      NULL

根据一些评论，我使用了以下查询：

SELECT DISTINCT IndividualId, IndividualName, TranId, Agent.AgentId, Amount 
FROM Individual 
LEFT JOIN Transactions 
ON   Individual.IndividualId = Transactions.IndId 
LEFT JOIN Agent 
ON   Transactions.AgentId = Agent.AgentId

这给出了以下不正确的结果：

IndividualId    IndividualName  TranId  AgentId Amount   
ind1            Mark            Tran1   Agent1  100  
ind1            Mark            Tran2   null    500  
ind2            Paul            null    null    null  
ind3            Spencer         Tran3   null    200 
ind4            Mike            Tran4   Agent3  50 
ind4            Mike            Tran5   null    30  
ind5            Hilary          null    null    null

Answer 1

试试这个：

SELECT Distinct IndividualId,  IndividualName, Agent.AgentId, TranId, Amount 
FROM Individual
Left join Agent ON Individual.IndividualId = Agent.IndId 
left join Transactions
  on Individual.IndividualId = Transactions.IndId  and  Transactions.AgentId = Agent.AgentId
  union 
    SELECT Distinct IndividualId, Name,  TranId,NUll as AgentId, Amount 
FROM Individual
left join Transactions
  on Individual.IndividualId = Transactions.IndId  and Transactions.AgentId is null

坚持使用sql连接

1 个答案: