Question

无法理解此SQL查询中的错误：

USE [My_db]
GO

SELECT ItemId
      ,Subject
      ,CreatedOn
  FROM ItemBase AS e
      INNER JOIN ItemExtensionBase AS p
      ON e.ItemId = p.ItemId
GO

错误：

 Msg 209, Level 16, State 1, Line 4
 Ambiguous column name 'ItemId'.

两个表中都存在

ItemId列。

Answer 1

USE [My_db]
GO

SELECT e.ItemId
      ,Subject
      ,CreatedOn
  FROM ItemBase AS e
      INNER JOIN ItemExtensionBase AS p
      ON e.ItemId = p.ItemId
GO

您需要告诉它从

中取出itemid字段的表

Answer 2

使用e.ItemId或p.ItemId：

USE [My_db]
GO

SELECT e.ItemId
      ,Subject
      ,CreatedOn
  FROM ItemBase AS e
      INNER JOIN ItemExtensionBase AS p
      ON e.ItemId = p.ItemId
GO

SQL server ERROR不明确的列名

2 个答案: