Unterminated dollar-quoted string creating PostgreSQL function - postgresql

Question

Using PostgreSQL 12.3, I am having some trouble trying to validate this simple chunk of plpgsql code
create or replace function test()
returns void
as $$
begin
prepare plan as select 1;
execute plan;
end;
$$ language plpgsql;
Error is
Unterminated dollar-quoted string at or near "$$ begin prepare plan as select 1;"
I have tried with and without ; after end. I have also tried with sql instead of plpgsql.
Any idea of whats is wrong?
This is a db-fiddle to quickly test the code:
https://www.db-fiddle.com/f/KgRZcxXqJs2Lwe284Mj5y/3

Answer 1

The issue is not with the $$ quoting:
create or replace function test()
returns void
as $$
begin
prepare plan as select 1;
execute plan;
end;
$$ language plpgsql;
CREATE FUNCTION
select test();
ERROR: column "plan" does not exist
LINE 1: SELECT plan
^
QUERY: SELECT plan
CONTEXT: PL/pgSQL function test() line 4 at EXECUTE
When you run this in the dbfiddle the full error output is:
Schema Error: error: unterminated dollar-quoted string at or near "$$ begin prepare plan as select 1;"
Schema Error: error: prepared statement "plan" does not exist
Schema Error: error: unterminated dollar-quoted string at or near "$$ language plpgsql;"
Query Error: error: function test() does not exist
The issue is that EXECUTE inside plpgsql is its own command:
https://www.postgresql.org/docs/12/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
EXECUTE command-string [ INTO [STRICT] target ] [ USING expression [, ... ] ];
I would use the plpgsql form. This works:
create or replace function test()
returns void
as $$
begin
prepare plan as select 1;
EXECUTE 'execute plan';
RAISE NOTICE 'Made it';
DEALLOCATE plan;
end;
$$ language plpgsql;
select test();
NOTICE: Made it
test
------
(1 row)