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From:Augey Mikus Date:May 10 2002 10:13pm
Subject:Re: quick sql question
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so i suppose an automatic delete of every duplicate record is out of the 
question :-)

Paul DuBois wrote:

> At 18:00 -0400 5/10/02, Augey Mikus wrote:
>
>> is there a way for me to do it in a mysql delete statement?  just out 
>> of curiosity, for instance, if i wanted to add duplicates later for 
>> whatever reason.
>
>
> Okay, let's suppose you have 3947 instances of "abc".
> You can use LIMIT for this:
>
> DELETE FROM tbl_name WHERE col_name = "abc" LIMIT 3946;
>
>
>>
>> Paul DuBois wrote:
>>
>>> At 17:54 -0400 5/10/02, Augey Mikus wrote:
>>>
>>>> what i meant is deleting duplicate occurences of records of a 
>>>> certain field. ...sorry...
>>>
>>>
>>>
>>> Ah.
>>>
>>> One thing you can do is add a unique index on that field with
>>> ALTER IGNORE TABLE tbl_name ADD UNIQUE (col_name)
>>> or
>>> ALTER IGNORE TABLE tbl_name ADD PRIMARY KEY (col_name)
>>>
>>> and MySQL will clobber duplicate records as it builds the index.
>>>
>>>>
>>>>
>>>> Paul DuBois wrote:
>>>>
>>>>> At 17:16 -0400 5/10/02, Augey Mikus wrote:
>>>>>
>>>>>> what is the simplest way to delete duplicate occurences of a 
>>>>>> specific field in mysql?
>>>>>>
>>>>>> thanks,
>>>>>>
>>>>>> augey
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Your question is a bit ambiguous.  You could do this by using ALTER
>>>>> TABLE to remove the column itself from the table, for example, but
>>>>> I'm guessing maybe that's not what you mean.
>>>>
>
>



Thread
quick sql questionAugey Mikus10 May
  • Re: quick sql questionPaul DuBois10 May
  • Re: quick sql questionAugey Mikus10 May
    • Re: quick sql questionPaul DuBois10 May
  • Re: quick sql questionAugey Mikus10 May
    • Re: quick sql questionPaul DuBois10 May
  • Re: quick sql questionAugey Mikus11 May
  • Re: quick sql questionAugey Mikus11 May
    • Re: quick sql questionPaul DuBois11 May
      • Repair with key cachesup-mysql11 May
        • Re: Repair with key cacheBenjamin Pflugmann11 May
          • Re: Repair with key cachesup-mysql11 May
            • Re: Repair with key cachePaul DuBois12 May
              • Re: Repair with key cachesup-mysql12 May
              • Re: Repair with key cachesup-mysql12 May
                • Re: Repair with key cachePaul DuBois12 May
                  • Re: Repair with key cachesup-mysql12 May
                    • Re: Repair with key cacheJeremy Zawodny12 May
                      • RE: Repair with key cacheRamon Arias13 May
                        • Re: Repair with key cacheJeremy Zawodny13 May
  • Re: quick sql questionAugey Mikus11 May