重複查詢

Question

有人可以幫我這個查詢請：

我有哪裏的客戶有多個記錄的數據（在一個單一的表，這是讀入一個表中的平面文件），例如

Name Policy 
Fred SSS 
Fred SST 
Joe SSS 

我需要提取所有記錄，其中Policy ='SSS'但該客戶只有'SSS'策略。因此，只有喬從上空

Answer 1

select name 
from yourtable 
group by name 
having count(policy)=1 and max(policy)='SSS' 

Answer 2

SELECT Name 
FROM tableName a 
WHERE Policy = 'SSS' 
GROUP BY Name 
HAVING COUNT(*) = (SELECT COUNT(*) FROM tableName b WHERE a.Name = b.Name) 

SQLFiddle Demo