Re: User input to queries

On Wed, 2020-12-09 at 09:03 -0800, Rich Shepard wrote:
> While I develop the application's GUI I use the database from the command
> line (psql). While some queries are self-contained others need user input.
> I've not found a search term that locates this information in the
> postgres-12 user manual and my web searches suggest that using '&' should
> work.
>
> I tried the latter with this query but postgres didn't like it. (There may
> well be other errors in it so don't hesitate to point out my mistakes.)
>
> ------
> /* This query selects all activity information for a named person */
>
> /* Specify columns */
> SELECT p.lname, p.fname, p.loc_nbr, p.job_title, p.direct_phone, p.active,
> o.org_name,
> l.loc_nbr, l.loc_name,
> a.act_date, a.act_type, a.notes, a.next_contact
> /* Specify tables. */
> FROM People AS p
> JOIN Organizations AS o ON o.org_nbr = p.org_nbr
> JOIN Locations AS l ON l.org_nbr = o.org_nbr and l.loc_nbr = p.loc_nbr
> JOIN Activities AS a ON a.person_nbr = p.person_nbr
> /* Specify rows */
> WHERE p.lname = &p.lname AND p.fname = &p.fname;
> -----
>
> Suggestions on what I should read to learn more about this subject are
> appreciated.

You probably need the \prompt psql command:

\prompt 'What is "p.lname"' p_lname
\prompt 'What is "p.fname"' p_fname
SELECT ... WHERE p.lname = :p_lname AND p.fname = :p_fname;

Yours,
Laurenz Albe
--
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