sql中列的别名 [英] alias name in sql for columns

问题描述

嗨朋友

为什么这个查询错了?

hi friend

why is this query wrong??

SELECT [Code],sum([Value]) as COL
  FROM [Stuff] where COL=250 GROUP BY [Code]

请指导我

please guide me

推荐答案

您不能在where子句中使用别名作为元素.您可能会执行以下操作

You can not be using an alias as an element in the where clause. Possibly you may do the following

Select code, sum(value) as col
  from table
 having sum(value) = 250
 group by code

在过滤记录后执行列命名操作.因此，当进程尝试执行COL = 25过滤器时，找不到任何名称为COL的列.

Column naming action perform after filtering the record. So when process try to execute COL=25 filter, it do not find any column with the name COL.

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