> > >maybe this is a silly question but how useful it is to create indexes
> >>columns containing only values 0 and 1 (true and false)?
> > Perhaps, instead of the index, you might revise your schema a bit.
> > Why do you have this boolean column? What are you trying to
> > achieve?
> I use boolean columns as a flags mostly to mark records as 'exported'. For
> example I have table 'Transactions' and I have to export data for some of
> our customers (never for all of them).
Right. Flags. IMO, flags are bad.
And, as you noticed, it will slow down any queries because a flag cannot
be indexed properly.
Instead, why create a table
TransactionID <primary key>
This can be indexed and will be fast if you want to get info about
any exported transactions.
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