Обсуждение: DISTINCT peformance differences

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DISTINCT peformance differences

От
"Christopher Kings-Lynne"
Дата:
If art_id is the primary key of the la table, is the latter faster?

SELECT DISTINCT la.* FROM <join> ...

or

SELECT DISTINCT ON (la.art_id) la.* FROM <join> ...

ie. Does this offer a performance improvement by only doing the distinct on
the primary key or not?

Thanks,

Chris