Using Substitution Variables In PostgreSQL

[Osahon Oduware <osahon.gis@xxxxxxxxx>]

Hi All,

I wanted to find out how to use a substitution variable in an SQL statement that would cause the user to be prompted for a value. Something similar to the ampersand (&&) in ORACLE.

For example, given the SQL statement below:
    SELECT <col1>,<col2>,<col3>
    FROM <table>
    WHERE <col5> = 35

I want the user to be prompted for the value in the WHERE (filter) clause, e.g.
    SELECT <col1>,<col2>,<col3>
    FROM <table>
    WHERE <col5> = ?

I would be glad if someone could point me in the right direction.