Re: COPY from .csv File and Remove Duplicates
| От | David Johnston |
|---|---|
| Тема | Re: COPY from .csv File and Remove Duplicates |
| Дата | |
| Msg-id | 6CA55C4C-D5C4-43DE-9B35-99C2D6622E4D@yahoo.com обсуждение исходный текст |
| Ответ на | Re: COPY from .csv File and Remove Duplicates (Rich Shepard <rshepard@appl-ecosys.com>) |
| Ответы |
Re: COPY from .csv File and Remove Duplicates
Re: COPY from .csv File and Remove Duplicates |
| Список | pgsql-general |
> A pointer to the appropriate syntax for retrieving the entire row when > count(loc_name, sample_date, param) > 1 would be much appreciated. > > Rich > Select * From table Natural Inner join ( SELECT loc_name, sample_date, param, Count(*) as duplicate_count FROM table Group by loc_name, sample_date, param ) grouped Where duplicate_count > 1 ; You first group and count on the candidate key and then effectively self-joint that result back onto the original table. natural join is short-hand for cases where the two joining table use the same name for semantically identical field. Much easier than saying "t1.field1 = t2.field1 AND t1.field2 = t2.field2 AND etc..." David J.
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