无法绑定多部分标识符的原因

Question

错误 - 无法绑定多部分标识符"Grant.EmpID".

查询 -

select emp.EmpID, 
COUNT(*) as CountRecords,
COUNT(GrantName) AS CountValues
From Employee as emp full join [Grant] as gr
on emp.EmpID = [Grant].EmpID 
-- This is the cause for the error ! Change it to gr.EmpID
group by emp.EmpID

为什么会出现此错误？我不能用真名和昵称叫一个人吗？

Answer 1

你是别名[Grant].换句话说,你说从现在开始,[Grant]将被称为gr.

使用ALIASin GROUP BY子句,而不是tableName.

SELECT emp.EmpID, 
       COUNT(*) as CountRecords,
       COUNT(GrantName) AS CountValues
FROM   Employee as emp 
       FULL JOIN [Grant] as gr
          on emp.EmpID = gr.EmpID  -- use the alias.
GROUP BY gr.EmpID                  -- use the alias.

这是SQL的操作顺序

• FROM子句
• WHERE子句
• GROUP BY子句
• HAVING子句
• SELECT子句
• ORDER BY子句