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Realted to the UNION in sql

  • January 6, 2010 at 9:50 am

    #215204

    Hi all,

    Let say there are two select statement and we are using UNION to combine result from both select statement.

    Now the problem lies here:

    Let say that first select statement returns these rows

    ColumnA

    A

    A

    B

    C

    And second select statement return these rows

    ColumnB

    B

    C

    D

    D

    Now can any one please tell me what will be the result of the query where we are using union between those above select statements.

    Thanks

    Rajneesh

  • January 6, 2010 at 9:58 am

    #1099729

    The result will be ABCD (ie four rows with an implicit distinct from the union, or you could use union all if you do not want the implied distinct.

    Not sure I understand why it is a problem though...

    Mike

  • January 7, 2010 at 7:39 pm

    #1100662

    ...and if you don't want to remove the duplicates, use UNION ALL rather than UNION.

    Paul White
    SQLPerformance.com
    SQLkiwi blog
    @SQL_Kiwi

  • January 7, 2010 at 10:40 pm

    #1100694

    The answer is ABCD

    as union remove all the duplicate values

    if You want to retain all values please use UNION ALL 🙂

  • January 7, 2010 at 10:47 pm

    #1100698

    kiranbgiet (1/7/2010)

    The answer is ABCD

    as union remove all the duplicate values

    if You want to retain all values please use UNION ALL 🙂

    Thank you for your valuable contribution 😛

    Paul White
    SQLPerformance.com
    SQLkiwi blog
    @SQL_Kiwi

  • January 7, 2010 at 10:59 pm

    #1100700

    To OP - not to sound harsh but pls lookup BOL and then ask your doubts. A Few doubts can be cleared by checking BOL.

    Hope my comments will be appreciated.

    "Keep Trying"

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