Returning table results from a dynamic PL/SQL query - plsql

Question

Trying to dynamically generate and execute a PL/SQL statement. It doesn't return results, but executing okay. What I am trying is to get the table name from the schema in first statement (got it right!), and append that to a select statement, and then execute it to return the table results.
DECLARE
LATEST_TABLE VARCHAR2(256);
PostalCode ADM.POSTAL_CODE_201801%ROWTYPE;
BEGIN
SELECT TO_CHAR(max(table_name)) INTO LATEST_TABLE FROM all_tables WHERE owner = 'ADM' AND table_name LIKE 'POSTAL_CODE_%';
LATEST_TABLE := 'begin Select POSTALCODE,LONGITUDE,LATITUDE,MUNICIPALITY_FULL_NAME,LOCAL_NAME,SZONE_NAME,ZONE_NAME,RHA_CODE,RHA_NAME,URBAN,ZONE_RURAL from ADM.'||LATEST_TABLE||' ;end;';
execute immediate LATEST_TABLE into PostalCode;
Exception
When others then
Null;
END;
Why am I not getting any results? Adding
dbms_output.put_line(PostalCode.LONGITUDE || PostalCode.LATITUDE); after execute immediate is also not generating results!

Answer 1

I see a couple of issues here; your code is something like:
declare
vSQL varchar2(1000);
vTabName varchar2(30);
vResult number;
begin
select table_name into vTabName from user_tables;
vSQL := 'begin select a from ' || vTabName || '; end;';
execute immediate vSQL into vResult;
dbms_output.put_line('REsult: ' || vResult);
exception
when others then
null
end;
If you run this, you see nothing, because the dynamic part gives error, but the (dangerous) exception handling hides it; if you would edit the null; into something like
dbms_output.put_line('Error: ' || sqlerrm);
you would get:
Error: ORA-06550: line 1, column 7:
PLS-00428: an INTO clause is expected in this SELECT statement
In fact you dynamic code is like
begin select a from someTable; end;
and this gives error.
A way to do what you need could be:
...
vSQL := 'select a from ' || vTabName;
execute immediate vSQL into vResult;
...