On Mon, Jan 23, 2017 at 12:53 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Corey Huinker <corey.huinker@gmail.com> 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.
regards, tom lane
That'd work too, if \if and defined(psql_var_name) come to fruition.
A use case we have now is where a script has several values that are almost always a default value.
