Why did MS provide LEFT and RIGHT OUTER JOIN?

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  13 years ago

  by khari6579

  Hari K

  Chennai, India

  Joined 15 years ago

   Dear Developers,

   I hv one doubt....  herewith explain my doubt with eample

   tblItem_M  : Item_Code, Item_Desc

   tblOrder  : Order_ID,Item_Code,Qty,Price...

    When i use

     SELECT M.Item_Code,M.Item_Desc FROM tblItem_M M
  

                LEFT OUTER JOIN tblOrder O ON M.Item_Code=O.Item_Code

    SELECT M.Item_Code,M.Item_Desc FROM tblOrder O

                RIGHT OUTER JOIN tblItem_M M ON O.Item_Code=M.Item_Code
  
  

   In the above both SQL query will return same data...in the second query also return the same records that what i got in the first query...but  i m using RIGHT OUTER JOIN and inter change the table.
  

  My doubt is why did Microsoft provide  both LEFT and RIGHT OUTER JOIN. we can achieve LEFT OUTER JOIN itself other wise RIGHT OUTER JOIN itself just interchange the table...
  

  great tips would be appreciated...tnx in advance...

  Regards 

  Hari K......
   

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