Question

我如何选择显示有贷款但没有dda且没有相关行为类型的custid，除非只有actype L？寻找没有dda关系的记录，即使它们是联合相关的（cfrela = J）。如下所述，A123和B128符合条件，但由于与DDA账户的联合关系，相关的A123 D actype被取消资格。 L =贷款，D = DDA，S =储蓄

SELECT loans.custid, dda.custid, related.custid
FROM data.lnmast lnmast 
EXCEPTION JOIN data.dda dda         
ON loans.custid = dda.custid
JOIN data.related related
ON loans.custid = related.custid

LOANS       
custid(c)   actype(c)   
A123           L    
B128           L    

DDA     
custid(c)   actype(c)   
A125           D    

RELATED     
custid(c)   actype(c) cfrela(c)
A123          D         J
A123          L         P
A123          S         J
B128          L         P
B128          L         P

Answer 1

如果我正确理解您的问题，您希望显示dda表中不存在的客户ID，并且仅存在于actype = L的相关表中？

SELECT L.CustId
FROM Loans L 
   LEFT JOIN Related R ON L.custid = R.custId AND R.actype <> 'L'
   LEFT JOIN DDA D ON L.custid = D.custid
WHERE d.custid IS NULL AND R.custid is NULL

如果必须在Related表中有记录，那么再添加一个INNER JOIN：

SELECT DISTINCT L.CustId
FROM Loans L 
   INNER JOIN Related R1 ON L.custid = R1.custId AND R1.actype = 'L'
   LEFT JOIN Related R ON L.custid = R.custId AND R.actype <> 'L'
   LEFT JOIN DDA D ON L.custid = D.custid
WHERE d.custid IS NULL AND R.custid is NULL

希望这有帮助。

Answer 2

解决此问题的一种方法是使用left outer join：

select l.*
from data.lnmast l left outer join
     (select *
      from data.dda
      where actype <> 'L'
     ) dda
     on l.custid = dda.custid left outer join
     data.related r
     on l.custid = dda.custid
where dda.custid is null and r.custid is null

where子句根据您的逻辑选择不匹配的记录。

多个表的SQL连接

2 个答案: