在OVER（）子句中使用别名

Question

可以通过row_number() OVER()编号结果计数行吗？

例如

SELECT *, 
    users::numeric/population::numeric*100 AS penetration, 
    row_number() OVER(ORDER BY penetration DESC) 
FROM states ORDER BY penetration DESC 

产生一个错误：

ERROR: column "penetration" does not exist 

Answer 1

你不能这样做在postgresql中。寻找expression这里：4.2.8. Window Function Calls，它说：..它不能输出列名或号码..

您可以通过用户的子查询：

SELECT states.*, penetration, row_number() OVER(ORDER BY penetration DESC) 
    FROM states 
    JOIN (SELECT id, users::numeric/population::numeric*100 AS penetration 
      FROM states) s_pen on spen.id = states.id 
ORDER BY s_pen.penetration DESC 

Answer 2

我不使用postgre但对于T-SQL，你必须做这样的事情：

SELECT *, 
    penetration, 
    row_number() OVER(ORDER BY penetration DESC) 
FROM 
(
    select users::numeric/population::numeric*100 AS penetration 
    from states 
)pen 
ORDER BY penetration DESC