On 3/4/23 19:22, Tom Lane wrote:
Ron <ronljohnso...@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';".
postgres=# \set foo BAR
postgres=# select :'foo';
?column?
----------
BAR
(1 row)
postgres=# select $$ :foo $$;
?column?
----------
:foo
(1 row)
postgres=# select $$ :'foo' $$;
?column?
----------
:'foo'
(1 row)
--
Born in Arizona, moved to Babylonia.
