Ron <ronljohnsonjr@gmail.com> writes:
> According to
> https://www.postgresql.org/docs/12/app-psql.html#APP-PSQL-VARIABLES and
> experience, variables don't interpolate inside of string literals:
> "
> Variable interpolation will not be performed within quoted SQL literals and
> identifiers. Therefore, a construction such as ':foo' doesn't work to
> produce a quoted literal from a variable's value.
> "
> But crosstab takes text strings as parameters. How then do you use \set
> variables in crosstab queries?
If you read a little further, you'll find out the syntax for converting
the value of a psql variable to a SQL string literal:
regression=# \set foo BAR
regression=# select ':foo';
?column?
----------
:foo
(1 row)
regression=# select :'foo';
?column?
----------
BAR
(1 row)
What the server got in the last case was "select 'BAR';".
regards, tom lane
