Pass SQL string to oracle stored procedure and get results with execute immediate - sql

Question

I am trying to pass in a SQL string to a stored procedure and using EXECUTE IMMEDIATE to return the results. Something like this:
CREATE PROCEDURE P360_RCT_COUNT (sqlString IN VARCHAR2)
AS
BEGIN
EXECUTE IMMEDIATE sqlString;
END;
/
I am not sure how to accomplish it. With the above, when I execute the SP using the command below, I get an error:
EXECUTE P360_RCT_COUNT 'SELECT COUNT(DISTINCT ENTITY_ID),ADDR_COUNTY FROM P360_V_RCT_COUNT GROUP BY ADDR_COUNTY';
The error is: ORA-06550: line 1, column 22:
PLS-00103: Encountered the symbol "SELECT COUNT(ENTITY_ID),ADDR_COUNTY
FROM P360_V_RCT_COUNT GROUP " when expecting one of the following:
:= . ( # % ; The symbol ":=" was substituted for "SELECT
COUNT(DISTINCT ENTITY_ID),ADDR_COUNTY FROM P360_V_RCT_COUNT GROUP " to
continue.
Basically I am building a SQL string in a system and need to pass it in to the SP and get the results back to the system. I am relatively new to stored procedures in Oracle.

Answer 1

The easiest way to work with a result set is sys_refcursor. This can be used quite easily with JDBC or ODBC.
Your procedure would look like this:
CREATE PROCEDURE P360_RCT_COUNT (
sqlString IN VARCHAR2
, p_result_set out sys_refcursor)
AS
BEGIN
open p_result_set for sqlString;
END;
/
Obviously the precise details of how you call it will vary according to your client. But in SQL*Plus it would be:
var rc refcursor
exec P360_RCT_COUNT( 'SELECT COUNT(DISTINCT ENTITY_ID),ADDR_COUNTY FROM P360_V_RCT_COUNT GROUP BY ADDR_COUNTY', :rc);
print rc

Answer 2

To return lists of values in a OUT parameter you need to decide the type(s) to use.
Say, for example, you have to return some varchar2 and some date lists, you could use something like this:
create or replace type tabOfVarchar2 is table of varchar2(100);
create or replace type tabOfDates is table of date;
create or replace procedure testProc(pString IN varchar2,
pOutVarchar1 OUT tabOfVarchar2,
pOutVarchar2 OUT tabOfVarchar2,
pOutVarchar3 OUT tabOfVarchar2,
pOutDates OUT tabOfDates
) is
begin
execute immediate pString
bulk collect into pOutVarchar1, pOutVarchar2, pOutVarchar3, pOutDates;
end;
This is way you can test this procedure:
declare
v1 tabOfVarchar2 ;
v2 tabOfVarchar2;
v3 tabOfVarchar2;
d1 tabOfDates ;
vSQL varchar2(100) := 'select ''a'', ''b'', ''c'', sysdate from dual';
begin
testProc(vSQL, v1, v2, v3, d1);
--
for i in v1.first .. v1.last loop
dbms_output.put_line(v1(i) || '/' || v2(i) || '/' || v3(i) || '/' || to_char(d1(i), 'dd/mm/yyyy'));
end loop;
end;
which gives:
a/b/c/14/04/2017
This only works with queries that give exactly a fixed number of columns, of known types.