PL/SQL: ORA-00932: inconsistent datatypes: expected UDT got NUMBER

Question

Hi all,
Wondering if you could assist? I'm exploring User Types and having a small problem. I'm getting the above error for a user type I have created which I'm calling in a function. Here's what my code looks like which I'm running the 'scott' schema for testing purposes
SQL> CREATE OR REPLACE TYPE NBR_COLL AS TABLE OF NUMBER;
2 /
Type created.
SQL> create or replace FUNCTION first_rec_only
2 (
3 NUM_ID IN NUMBER
4 ) RETURN NUMBER IS
5 v_num NBR_COLL;
6 BEGIN
7 select deptno into v_num from dept;
8 RETURN v_num(v_num.FIRST);
9 END first_rec_only;
10 /
Warning: Function created with compilation errors.
SQL> show errors
Errors for FUNCTION FIRST_REC_ONLY:
LINE/COL ERROR
7/4 PL/SQL: SQL Statement ignored
7/11 PL/SQL: ORA-00932: inconsistent datatypes: expected UDT got
NUMBER
SQL>
Any clues to what I'm doing wrong? Cheers.

Answer 1

The deptno column is a number, you cannot directly select a number into your type, you need to use your type's constructor.
Something like:
CREATE OR REPLACE FUNCTION first_rec_only (NUM_ID IN NUMBER) RETURN NUMBER IS
   v_num NBR_COLL;
BEGIN
   SELECT nbr_coll(deptno) INTO v_num from dept;
   RETURN v_num(v_num.FIRST);
END first_rec_only;Note that although this will compile, it will throw ORA-01422: exact fetch returns more than requested number of rows when you run it. you need to either use the input parameter as a predicate on your query against dept, use rownum = 1 in the query or use bulk BULK COLLECT INTO, depending on what exactly you want to accomplish.
John