将平均列添加到同一表中 [英] add average column into same table

问题描述

我有一个像这样的表:表1 我需要在该表中添加一列作为平均投放时间添加了avr_del_time列我的代码是:

I have a table like: Table1 And I need to add a column to that table as average delivery time avr_del_time column added My code is:

SELECT a.vendor, a.part_nr, a.delivery_time, b.avr_del_time
FROM  Table1 a
INNER JOIN (SELECT AVG(delivery_time) AS avr_del_time FROM Table1 GROUP BY vendor, part_nr) b
ON a.vendor = b.vendor, a.part_nr=b.part_nr

请指导我...

推荐答案

您的查询在正确的轨道上.您只需要解决SQL错误:

Your query is on the right track. You just need to fix up the SQL mistakes:

SELECT a.vendor, a.part_nr, a.delivery_time, b.avr_del_time
FROM Table1 as a INNER JOIN
      (SELECT  vendor, part_nr, AVG(delivery_time) AS avr_del_time
       FROM Table1
       GROUP BY vendor, part_nr
     ) as b
     ON a.vendor = b.vendor AND a.part_nr = b.part_nr;

注意:

• 在 GROUP BY 子查询中，您需要 SELECT 中的键.
• 您在 ON 条件下有一个逗号；它应该是 AND .
• 我建议您使用表别名(表名的缩写).

• In the GROUP BY subquery, you need the keys in the SELECT.
• You have a comma in the ON condition; it should be AND.
• I would suggest that you use table aliases that are abbreviations for the table names.

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