How to fix ORA-01422:- Fetch isnt working - oracle

Question

I'm not understanding why this error is occurring. I have seen examples with him but the people doesn't use the for or the fetch loop. As I have understood, the fetch would loop in all the output of the cursor, in this case, taking row by row of the query and avoiding this error.
See the code:
CREATE OR REPLACE TYPE tab_dias IS TABLE OF INTEGER;
CREATE OR REPLACE FUNCTION uf_dias_internado_paciente
(v_cod_paciente IN internacao.COD_PACIENTE%TYPE,
v_dt_inicio IN internacao.DT_HORA_ENTRADA %TYPE,
v_dt_fim IN internacao.DT_HORA_ALTA %TYPE)
RETURN tab_dias
IS
v_dias tab_dias := tab_dias();
CURSOR c_dias IS
SELECT EXTRACT(DAY FROM (i.DT_HORA_ALTA - i.DT_HORA_ENTRADA)) AS dias
FROM INTERNACAO i
WHERE i.COD_PACIENTE = v_cod_paciente
AND i.DT_HORA_ENTRADA >= v_dt_inicio --13
AND i.DT_HORA_ALTA <= v_dt_fim;
linha_dias c_dias%ROWTYPE;
BEGIN
OPEN c_dias;
LOOP
FETCH c_dias INTO linha_dias;
EXIT WHEN c_dias%NOTFOUND;
v_dias(v_dias.last) := linha_dias.dias;
END LOOP;
CLOSE c_dias;
RETURN v_dias;
END;
The error: ORA-01422: exact fetch returns more than requested number of rows
The code I'm running:
SELECT uf_dias_internado_paciente (5007, CURRENT_TIMESTAMP - 500000, CURRENT_TIMESTAMP ) FROM DUAL;
The desired output:
SELECT (EXTRACT(DAY FROM (i.DT_HORA_ALTA - i.DT_HORA_ENTRADA)))
FROM INTERNACAO i
WHERE i.COD_PACIENTE = 5007
AND i.DT_HORA_ENTRADA >= CURRENT_TIMESTAMP - 500000
AND i.DT_HORA_ALTA <= CURRENT_TIMESTAMP;
(EXTRACT(DAYFROM(I.DT_HORA_ALTA-I.DT_HORA_ENTRADA)))|
----------------------------------------------------|
11|
1|
1|
Oracle documentation:
https://docs.oracle.com/cd/B14117_01/appdev.101/b10807/06_ora.htm#i36655
https://docs.oracle.com/cd/B14117_01/appdev.101/b10807/13_elems020.htm

Answer 1

Code - as you wrote it - will return
ORA-06502: PL/SQL: numeric or value error: NULL index table key value
because you're missing v_dias.EXTEND. It can't fail with ORA-01422 (which is TOO_MANY_ROWS); cursors don't return it (unless you have a subquery - which you don't).
Therefore, there's something wrong in code you posted vs. what you are saying.
As I don't have your tables, here's an example based on Scott's EMP table:
SQL> CREATE OR REPLACE TYPE tab_dias IS TABLE OF INTEGER;
2 /
Type created.
SQL> CREATE OR REPLACE FUNCTION f_dias (par_deptno IN NUMBER)
2 RETURN tab_dias
3 IS
4 v_dias tab_dias := tab_dias ();
5
6 CURSOR c_dias IS
7 SELECT empno AS dias
8 FROM emp
9 WHERE deptno = par_deptno;
10
11 linha_dias c_dias%ROWTYPE;
12 BEGIN
13 OPEN c_dias;
14
15 LOOP
16 FETCH c_dias INTO linha_dias;
17
18 EXIT WHEN c_dias%NOTFOUND;
19 v_dias.EXTEND; --> this
20 v_dias (v_dias.LAST) := linha_dias.dias;
21 END LOOP;
22
23 CLOSE c_dias;
24
25 RETURN v_dias;
26 END;
27 /
Function created.
Testing:
SQL> SELECT f_dias (10) FROM DUAL;
F_DIAS(10)
--------------------------------------------------------------------------------
TAB_DIAS(7782, 7839, 7934)
Or:
SQL> SELECT * FROM TABLE(f_dias (10));
COLUMN_VALUE
------------
7782
7839
7934
SQL>
Instead of a loop, perhaps you should consider bulk collect; it is simpler and more efficient:
SQL> CREATE OR REPLACE FUNCTION f_dias (par_deptno IN NUMBER)
2 RETURN tab_dias
3 IS
4 v_dias tab_dias := tab_dias ();
5
6 CURSOR c_dias IS
7 SELECT empno AS dias
8 FROM emp
9 WHERE deptno = par_deptno;
10 BEGIN
11 OPEN c_dias;
12
13 FETCH c_dias BULK COLLECT INTO v_dias;
14
15 CLOSE c_dias;
16
17 RETURN v_dias;
18 END;
19 /
Function created.
SQL> SELECT * FROM TABLE (f_dias (10));
COLUMN_VALUE
------------
7782
7839
7934
SQL>
So, basically, it works. There's something else that produces TOO_MANY_ROWS, not code you posted.