按命令分组不会将我的查询结果分组

Question

Andddd我回来了！我试图在这个数据库中获得房地产销售的数量，并且我有足够的理由来整理所有的城镇销售情况。完善。我加入了一个小组，它应该按照他们所在的城镇来分组，但事实并非如此。我敢肯定它是一个愚蠢的错误，谁能告诉我我错过了什么？

SELECT rl.AgentID, rl.first_name, rl.last_name, Count(town) as Town 
FROM [INTERN_DB2].[dbo].[PaymentList] pl inner join 
(Select agentID, min(first_name) as first_name, min(last_name) as last_name 
    From [Intern_DB2]..[RealEstateAgentList] 
    GROUP BY agentID, first_name, last_name 
) rl 
ON rl.AgentID = pl.AgentID 
GROUP BY rl.AgentID, rl.first_name, rl.last_name, town; 

我在想我的错误是在计数命令，但我不知道。

Answer 1

你可能想从group by删除town：

SELECT rl.AgentID, rl.first_name, rl.last_name, Count(town) as Town 
FROM [INTERN_DB2].[dbo].[PaymentList] pl inner join 
(Select agentID, min(first_name) as first_name, min(last_name) as last_name 
    From [Intern_DB2]..[RealEstateAgentList] 
    GROUP BY agentID, first_name, last_name 
) rl 
ON rl.AgentID = pl.AgentID 
GROUP BY rl.AgentID, rl.first_name, rl.last_name; 

随着在group bytown，你指望匹配的编号为agentid/town组合。因此，一个特定的代理将在多行，每个城镇一个。然后它会给出与该代理关联的PaymentList中的行数。

你想做什么？如果要计算代理商所在的独特城镇，请执行以下操作：

SELECT rl.AgentID, rl.first_name, rl.last_name, Count(distinct town) as Town 
FROM [INTERN_DB2].[dbo].[PaymentList] pl inner join 
(Select agentID, min(first_name) as first_name, min(last_name) as last_name 
    From [Intern_DB2]..[RealEstateAgentList] 
    GROUP BY agentID, first_name, last_name 
) rl 
ON rl.AgentID = pl.AgentID 
GROUP BY rl.AgentID, rl.first_name, rl.last_name;