mysql - 我不明白我做错了什么

Question

If I run below query in my phpmyadmin it throw me below error

> Error in query (1054): Unknown column 'QTY' in 'where clause'

SELECT User_Name,
       COUNT(User_Name) AS QTY
FROM preusage
WHERE QTY > 1
GROUP BY User_Name

有人帮帮我

Answer 1

It is not allowable to refer to a column alias in a WHERE clause, because the column value might not yet be determined when the WHERE clause is executed.

但在你的情况下，我猜你想使用 having 无论如何(它可以使用以前定义的别名)

SELECT User_Name, COUNT(User_Name) as QTY 
FROM preusage 
GROUP BY User_Name
HAVING QTY > 1