2017-01-23 18:53 GMT+01:00 Tom Lane <[email protected]>: > Corey Huinker <[email protected]> writes: > > I was giving some thought to how psql handles undefined variables. > > I would like an option where either psql can provide an alternate value > > when an undefined variable is referenced, or a way to detect that a > > specific variable is undefined and replace it with a defined variable. > > This seems pretty bizarre. What's the use case? Why would it not > be better to build the behavior out of other spare parts, along the > lines of COALESCE or perhaps > > \if not defined(x) > \set x y > \fi > > Obviously the \if stuff is things we don't have yet either, but > it seems less likely to have surprising side-effects. >
Some form of DEFINED has more sense than COALESCE in this case. We can introduce some predefined client side functions available only in \if \elsif statements. Regards Pavel > > regards, tom lane > > > -- > Sent via pgsql-hackers mailing list ([email protected]) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers >
