Old style joins and SQL Server 2008+ RSS

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  MyronCope

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  Old style joins and SQL Server 2008+

  Jan 23, 2013 01:27 PM|LINK

  There is some legacy code here that is using the old-style (non ansi) joins, you know the

  <EXAMPLE>

  SELECT *

  FROM TableA, TableB

  WHERE TAbleA.ID=TableB.ID

  </EXAMPLE>

  The question I have is this:  will the old style joins such as the example above still work in sql server versions after SQL Server 2008?

  Are there performance issues in using the old style joins in SQL Server 2008?

  thanks

  MC

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  Dan Bracuk

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  Re: Old style joins and SQL Server 2008+

  Jan 23, 2013 01:39 PM|LINK

  They will work and will probably be slower than joining in the from clause.

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  limno

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  Re: Old style joins and SQL Server 2008+

  Jan 23, 2013 03:44 PM|LINK

  The join syntax (old-style) you are using is ANSI SQL-89 standard syntax:
  
  SELECT * FROM TableA, TableB WHERE TAbleA.ID=TableB.ID
  
  The newer one is ANSI SQL-92 syntax with JOIN:
  SELECT * FROM TableA  INNER JOIN TableB ON TAbleA.ID=TableB.ID
  
  Both of them are fully supported by database engine and interpreted in the same way.
  You will not see any performance difference between the two. But the newer one (SQL-92) is safer to write code.

  Limno
  
  Format your SQL query with instant sql formatter:
  http://www.dpriver.com/pp/sqlformat.htm
  • Marked as answer by Catherine Shan - MSFT on Jan 30, 2013 04:06 AM
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  wmec

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  Re: Old style joins and SQL Server 2008+

  Jan 24, 2013 02:49 AM|LINK

  Read

  http://www.sqlservercentral.com/blogs/brian_kelley/2009/9/30/the-old-inner-join-syntax-vs-the-new-inner-join-syntax/

  Many Thanks & Best Regards,
  HuaMin Chen