sql-serversql-server-2008inner-join

SQL server ERROR Ambiguous column name

Can't understand what's wrong in this SQL query:

USE [My_db]
GO

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

Error:

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

ItemId column exist in both tables.

Solution 
  • USE [My_db]
GO

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

    You need to tell it which table to take the itemid field from