Wednesday, May 20, 2009

MySQL:Set up unique key ignoring duplicates

For many of you who might be having trouble setting up a unique key on
a table containing duplicates, here's the key

mysql> ALTER IGNORE TABLE table_name ADD UNIQUE(column_name)

Please note the keyword IGNORE in the above statement. That does the
work forcefully.

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5 comments:

  1. chorny3:54 AM

    "If IGNORE is specified, only the first row is used of rows with duplicates on a unique key, The other conflicting rows are deleted. Incorrect values are truncated to the closest matching acceptable value." - don't use this if you want duplicates to remain.

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  2. Ketan5:55 AM

    Yes, that's true. But if your application is in the development mode, you can save time with IGNORE. Is there any better way? If you know, please post here :-)

    Thank you Chorny!

    Ketan

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  3. Anonymous10:35 AM

    This comment has been removed by a blog administrator.

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  4. Anonymous2:19 PM

    It is useful to try everything in practise anyway and I like that here it's always possible to find something new. :)

    ReplyDelete
  5. Anonymous9:02 AM

    Nice dispatch and this enter helped me alot in my college assignement. Thank you on your information.

    ReplyDelete