Re: How to remove duplicate lines but save one of the lines?

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От Said Ramirez
Тема Re: How to remove duplicate lines but save one of the lines?
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Msg-id 4884B5D4.5030901@vonage.com
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Ответ на Re: How to remove duplicate lines but save one of the lines?  ("A B" <gentosaker@gmail.com>)
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Yes, here foo is a temp table. As others have pointed out, you could
probably do a create table foo as select distinct * from orig_table. I
would move the data back to orig_table, so that constraints and
privileges are maintainited. After you have done this, you can put a
uniq constraint on columns A & B.  I am uncertain if you can do
something like ALTER TABLE orig_table ADD UNIQUE (A,B) ON DUPLICATE DELETE.
   -Said

A B wrote:
>  > There is probably a more elegant way of doing it, but  a simple way
> of doing
>  > it ( depending on the size of the table ) could be:
>  >
>  > begin;
>  >
>  > insert into foo select distinct * from orig_table;
>  > delete from orig_table;
>  > insert into orig_table select * from foo;
>  >
>  > commit;
>
> Just to make it clear to me
> Here foo is a table that I have to create  with the command
> CREATE TABLE foo (....same columns as orig_table);
> ?
>
> Is it possible to add a unique constraint to the table, with a
> "delete" option so it will delete duplicates?
>
> --
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--
Said Ramirez
Super Cool MySQL DBA
cel: 732 425 1929

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