execute immediate with $$ - sql

Question

I have a long query that returns 1 column and 1 row:
Query 1:
select test_query from (
SELECT
LISTAGG('...') ... AS xx,
LISTAGG('"' || c.COLUMN_NAME || '"', ', ') WITHIN GROUP(ORDER BY c.COLUMN_NAME) AS column_list
.....
FROM INFORMATION_SCHEMA.COLUMNS c
WHERE TABLE_NAME = xx);
The output looks like this. It has a query that I want to run. Note that it consists of quotation marks. The original query 1 also has quotation marks in the LISTAGG.
output:
test_query
select "col1", "col2" from stg.new
I wanted to extend the Query A such that I can select and run the test_query and return the final output of the test_query instead of queryA. I tried using execute immediate with $$:
execute immediate
$$select test_query from (
SELECT
LISTAGG('...') ... AS xx,
LISTAGG('"' || c.COLUMN_NAME || '"', ', ') WITHIN GROUP(ORDER BY c.COLUMN_NAME) AS column_list
.....
FROM INFORMATION_SCHEMA.COLUMNS c
WHERE TABLE_NAME = xx)$$;
but instead of running the test_query it outputs the same thing as Query1.
What else can I try?

Answer 1

Here's an attempted conversion of your SQL template. You can extend it to add the entire SQL statement:
execute immediate
$$
declare
rs resultset default (
select test_query from (
SELECT
LISTAGG('...') ... AS xx,
LISTAGG('"' || c.COLUMN_NAME || '"', ', ') WITHIN GROUP(ORDER BY c.COLUMN_NAME) AS column_list
.....
FROM INFORMATION_SCHEMA.COLUMNS c
WHERE TABLE_NAME = xx);
);
c cursor for rs;
sqlStatement string;
rsFinal resultset;
begin
for rowContents in c do
sqlStatement := rowContents.SQL_STATEMENT;
end for;
rsFinal := (execute immediate :sqlStatement);
return table(rsFinal);
end;
$$
;
In case that's not working because of context, etc., here is a completely self-contained sample that's working:
create or replace transient table T1 as
select 'Hello world' as s;
create or replace transient table SQL_TO_RUN as
select 'select S from T1 SQL_STATEMENT' SQL_STATEMENT
;
execute immediate
$$
declare
rs resultset default (select SQL_STATEMENT from SQL_TO_RUN);
c cursor for rs;
sqlStatement string;
rsFinal resultset;
begin
for rowContents in c do
sqlStatement := rowContents.SQL_STATEMENT;
end for;
rsFinal := (execute immediate :sqlStatement);
return table(rsFinal);
end;
$$
;
Output:
S
Hello world