Having problems with this select in Oracle PLSQL - sql

Question

I have this code:
create view nombres_lab as
select L.NOMBRE_LAB, R.NOM_REG, count(*) as vacunas_suministradas
from LABORATORIOS L
inner join CREA_VACUNAS CV on l.cod_lab = cv.cod_lab
inner join vacunas V on cv.cod_vac = v.cod_vac
inner join vtorio VT on v.cod_vac = vt.cod_vac
inner join datos_vac_sum DVS on vt.cod_vtorio = dvs.cod_vtorio
inner join frasco_vac FV on dvs.s_unica = fv.s_unica
inner join direccion D on vt.cod_dir = d.cod_dir
inner join region R on d.cod_reg = r.cod_reg
where v.cod_vac = 100202 or v.cod_vac = 100303
group by l.nombre_lab, r.nom_reg;
create or replace procedure ranking is
begin
select nombre_lab, nom_reg, count(*) as vacunas_suministradas, rank() over(order by count(*) desc) as ranking from nombres_lab group by nom_reg, nombre_lab;
end;
I've been trying to convert this select to an select into so that it can work inside the procedure, but nothing that i try works.
Error: PLS-00428: an INTO clause is expected in this SELECT statement
I know its weird to do just a select in the procedure and nothing more, but i want to know if its possible

Answer 1

To answer your question (whether it is possible to do something like that): as Justin commented, it is (kind of), but you have to follow some rules.
For example (based on Scott's schema, as I don't have your tables):
SQL> CREATE OR REPLACE VIEW nombres_lab
2 AS
3 SELECT deptno nombre_lab, job nom_reg FROM emp;
View created.
This is a procedure which fixes error you got ("an INTO clause is expected in this SELECT statement"): declare some local variables and select into them.
SQL> CREATE OR REPLACE PROCEDURE ranking
2 IS
3 l_nombre_lab nombres_lab.nombre_lab%TYPE;
4 l_nom_reg nombres_lab.nom_reg%TYPE;
5 l_vacunas_suministradas NUMBER;
6 l_ranking NUMBER;
7 BEGIN
8 SELECT nombre_lab,
9 nom_reg,
10 COUNT (*),
11 RANK () OVER (ORDER BY COUNT (*) DESC)
12 INTO l_nombre_lab,
13 l_nom_reg,
14 l_vacunas_suministradas,
15 l_ranking
16 FROM nombres_lab
17 GROUP BY nom_reg, nombre_lab;
18 END;
19 /
Procedure created.
Will it work? Unfortunately, not. It would if query returned only one row, though:
SQL> EXEC ranking;
BEGIN ranking; END;
*
ERROR at line 1:
ORA-01422: exact fetch returns more than requested number of rows
ORA-06512: at "SCOTT.RANKING", line 8
ORA-06512: at line 1
So, what to do? You could use a loop (then you don't need any variables nor an into clause) and process values fetched. I don't have any smart ideas so I'm just displaying what cursor returned:
SQL> CREATE OR REPLACE PROCEDURE ranking
2 IS
3 BEGIN
4 FOR cur_r IN ( SELECT nombre_lab,
5 nom_reg,
6 COUNT (*) vacunas_suministradas,
7 RANK () OVER (ORDER BY COUNT (*) DESC) ranking
8 FROM nombres_lab
9 GROUP BY nom_reg, nombre_lab)
10 LOOP
11 DBMS_OUTPUT.put_line (
12 cur_r.nombre_lab
13 || ' - '
14 || cur_r.nom_reg
15 || ' - '
16 || cur_r.vacunas_suministradas
17 || ' - '
18 || cur_r.ranking);
19 END LOOP;
20 END;
21 /
Procedure created.
SQL> SET SERVEROUTPUT ON
SQL> EXEC ranking;
30 - SALESMAN - 4 - 1
20 - ANALYST - 2 - 2
20 - CLERK - 2 - 2
20 - MANAGER - 1 - 4
30 - CLERK - 1 - 4
30 - MANAGER - 1 - 4
10 - MANAGER - 1 - 4
10 - CLERK - 1 - 4
10 - PRESIDENT - 1 - 4
PL/SQL procedure successfully completed.
SQL>
Or, you could switch to a function that returns e.g. ref cursor:
SQL> CREATE OR REPLACE FUNCTION f_ranking
2 RETURN SYS_REFCURSOR
3 IS
4 rc SYS_REFCURSOR;
5 BEGIN
6 OPEN rc FOR SELECT nombre_lab,
7 nom_reg,
8 COUNT (*),
9 RANK () OVER (ORDER BY COUNT (*) DESC)
10 FROM nombres_lab
11 GROUP BY nom_reg, nombre_lab;
12
13 RETURN rc;
14 END;
15 /
Function created.
SQL> var l_rc refcursor
SQL> exec :l_rc := f_ranking
PL/SQL procedure successfully completed.
SQL> print l_rc
NOMBRE_LAB NOM_REG COUNT(*) RANK()OVER(ORDERBYCOUNT(*)DESC)
---------- --------- ---------- -------------------------------
30 SALESMAN 4 1
20 ANALYST 2 2
20 CLERK 2 2
20 MANAGER 1 4
30 CLERK 1 4
30 MANAGER 1 4
10 MANAGER 1 4
10 CLERK 1 4
10 PRESIDENT 1 4
9 rows selected.
SQL>
Therefore, yes - it is possible, but it depends on what you actually want to do.

Answer 2

The count(*) inside a rank function seems like an issue. Try below, I think that should solve the problem.
WITH nombre_lab_summary AS
(
SELECT
nombre_lab,
nom_reg,
COUNT(*) AS vacunas_suministradas,
FROM nombres_lab
GROUP BY
nom_reg,
nombre_lab
)
SELECT
*,
RANK() OVER (ORDER BY vacunas_suministradas DESC) AS ranking
FROM nombre_lab_summary
GROUP BY
nom_reg,
nombre_lab