Can you do a "SELECT DISTINCT"

In general, this is a bad thing to do. select distinct is a Red Flag. It may mean that you are making the database engine fetch a far larger result set than necessary. After it has fetched all that, you then tell it to filter the results and discard the duplicates. A much better approach would be to write the query correctly so that the distinct modifier becomes unnecessary.

It may mean that you that you need to consider a column that is not referenced specifically in the record set. The workaround may involve using a subselect, which is not available on databases like MySQL. In that case you are out of luck. Nonetheless, your first reflex should be to try and restructure your query. select distinct should be used only as a last resort.

erm, the "you" doesn't refer to scain here, it refers to you :)


print@_{sort keys %_},$/if%_=split//,'= & *a?b:e\f/h^h!j+n,o@o;r$s-t%t#u'

In reply to Re:x2 Escaping parentheses in regexps (select distinct is a Red Flag) by grinder
in thread Escaping parentheses in regexps by Tanalis

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