Re: Check psql parameter is passed, if not ask for it

to quote the documentation:

> If an unquoted colon (:) followed by a psql variable name appears within
an argument, it is replaced by the variable's value, as described in SQL
Interpolation below.
> The forms :'variable_name' and :"variable_name" described there work as
well. The :{?variable_name} syntax allows testing whether a variable is
defined. It is
> substituted by TRUE or FALSE. Escaping the colon with a backslash
protects it from substitution.

See https://www.postgresql.org/docs/16/app-psql.html

On Mon, Aug 5, 2024 at 8:46 PM Wiwwo Staff <wiwwo(at)wiwwo(dot)com> wrote:

> Hi!
> I want to check if I pass the parameter "param1" to a sql script
> "delme.sql" like
> ```
> \if ':param1'
> \echo :param1;
> \else
> \prompt 'Param1? ' :param1
> \endif
> select :'param1';
> ```
> if parameter `param1` is not passed, the .sql should ask for it.
>
> If I run something like
> `psql -f delme.sql -v param1=1`
> it works, but if i pass
> `psql -f delme.sql -v param1=meh`
> i receive
> `psql:delme.sql:1: error: unrecognized value ":param1" for "\if
> expression": Boolean expected`
>
> How can I implement that?
> TIA, Wiwwo
>