sql - 重复查询

Question

有人可以帮我解决这个问题吗：

我有客户有多个记录的数据（在一个表中，这是一个读入表的平面文件），例如

Name  Policy
Fred  SSS
Fred  SST
Joe   SSS

我需要提取 Policy='SSS' 但该客户只有“SSS”政策的所有记录。所以只有乔会从上面返回

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 演示