避免在SELECT中重复公式

Question

我们说我有以下内容：

SELECT 

    users_aggregate_data.treatment,

    SUM(users_aggregate_data.GS_Oct_Dec),
    AVG(users_aggregate_data.items_sold_Oct_Dec),
    --  .. and a few other such as std_deviation, ..

    SUM(users_aggregate_data.GS_Jan_Mar),
    AVG(users_aggregate_data.items_sold_Jan_Mar)
    --  .. and a few other such as std_deviation, ..

FROM users_aggregate_data

在users_aggregate_date中，我按客户和时间跨度精心汇总了销售数据。

我想知道是否有办法避免上面的所有样板代码。

Answer 1

您可以对表名使用别名（这会提高可读性），但您必须指定列名（如果您不想仅使用SELECT *）

SELECT d.treatment,
       SUM(d.GS_Oct_Dec),
       AVG(d.items_sold_Oct_Dec),
   --  .. and a few other such as std_deviation, ..
       SUM(d.GS_Jan_Mar),
       AVG(d.items_sold_Jan_Mar)
   --  .. and a few other such as std_deviation, ..
  FROM users_aggregate_data d

关于别名，您可以在此处阅读更多内容：SQL ALIAS Tutorial