having 子句在 sql 中不起作用

Question

我不明白这句话有什么问题。

  Select customername,LEN(address) 
  FROM customers group by customername having LEN(address) = 13;

这是错误信息 没有分组或聚合的 HAVING 子句 (LEN(address)=13)。

Answer 1

尝试使用 where 子句

  Select customername,LEN(address) as lenadressnamecolumn
  FROM customers where LEN(address) = 13;

Answer 2

address 和 LEN(address) 都不在 GROUP BY 中。因此，您需要添加它们或将表达式包装在聚合函数中：

SELECT customername, MAX(LEN(address))
FROM customers 
GROUP BY customername 
HAVING MAX(LEN(address)) = 13;

或者如果您只需要长度为 13 的客户，也许根本不需要聚合：

SELECT customername
FROM customers 
WHERE LEN(address) = 13;

having clause is not working in sql