PostgreSQL: How to pass parameters from command line?

Question

I have a somewhat detailed query in a script that uses ? placeholders. I wanted to test this same query directly from the psql command line (outside the script

Answer 1

You can use the -v construct e.g

psql -v v1=12  -v v2="'Hello World'" -v v3="'2010-11-12'"

and then refer to the variables in sql as :v1, :v2 etc

select * from table_1 where id = :v1;

Please pay attention on how we pass string/date value using two quotes " '...' "