sql - SQL 子查询语法检查其他记录

Question

我需要在表格中查找保费为 0 的保单，但如果另一个具有相同保单编号的保单具有保费，则不需要。这是我的伪代码：

select * from tblPolicies where premium = 0
(but not if anther record has the same policyNumber and premium <> 0)

我知道这很糟糕，但我迷路了，这是我能想到的最好的！

Answer 1

可能的问题 1：

SELECT M.* FROM tblPolicies AS M
WHERE premium = 0 AND policyNumber NOT IN 
(
   SELECT S.policyNumber 
   FROM tblPolicies AS S 
   WHERE S.policyNumber = M.policyNumber
   AND S.premium <> 0 
)

可能的问题 2：

SELECT SA.* FROM 
(
  SELECT M.* FROM tblPolicies AS M
  WHERE premium = 0
) AS SA
INNER JOIN tblPolicies AS SB
ON SA.policyNumber = SB.policyNumber 
WHERE SB.premium <> 0 

可能的问题 3：

SELECT * FROM tblPolicies AS SA
INNER JOIN tblPolicies AS SB
ON SA.policyNumber = SB.policyNumber 
WHERE SA.premium = 0 AND SB.premium <> 0 

Answer 2

select p_no from 
(select p_no, sum(premium) as tot_prem from policy group by p_no) as pol 
where tot_prem>0;

p_no-> premium_no

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