Count how many car/cars owner owns - sql

Question

I'm trying to learn plsql and got stuck in understanding some basic stuff. Here is a challenge that I'm trying to solve. I have two tables. One holds information about owners and the other is information about cars.
I want to to write an anonymous block that joins these two tables and with a for loop based on amount of cars that is registered to each owner prints how many cars each person own. furthermore I want an if statement which distinguishes between 1 Car (singular) and 2, 3 Cars (plural).
the tables are these:
CREATE TABLE owners(
id_nr VARCHAR2(13) PRIMARY KEY,
f_name VARCHAR2(20),
s_name VARCHAR2(20)
);
CREATE TABLE cars(
reg_nr VARCHAR2(6) PRIMARY KEY,
id_nr REFERENCES owners(pnr),
model VARCHAR2(20),
year NUMBER(4),
date DATE
);
The result may look like something like this:
19380321-7799, Hans, Anderson, Owns: 1 car
19490321-7899, Mike, Erikson, Owns: 2 cars
. . . etc
I know the this question was already answered but when I try following:
declare
v_suffix varchar2(1);
begin
for o in (select bilägare_pnr, fnamn, enamn,
(select count(1) from fordon where fordon_pnr = bilägare_pnr) as bilar_ägda
from bilägare)
loop
if o.pnr_fordon = 1
then v_suffix = 'bil'
else v_suffix = 'bilar'
end if;
dbms_output.put_line(o.pnr || ', ' || o.fnamn || ', ' || o.enamn
|| ' Äger: ' || o.pnr_fordon || ' bil' || v_suffix);
end loop;
end;
/
I get:
ORA-06550: line 9, column 27:
PLS-00103: Encountered the symbol "=" when expecting one of the following:
:= . ( # % ;
any tips? Im not sure how to declare v_suffix
EDIT (copied from comment on answer below):
Updating my code:
declare
cursor c_BILÄGARE is
select fnamn,enamn,pnr
from BILÄGARE;
begin
for rec in c_BILÄGARE loop
if (rec.antal>1) then
dbms_output.put_line (rec.pnr||','|| rec.fnamn || ',' ||
rec.enamn || ',' || rec.antal || 'bilar');
else
dbms_output.put_line (rec.pnr||','|| rec.fnamn || ',' ||
rec.enamn || ',' || rec.antal || 'bil');
end if;
end loop;
end;
getting:
ORA-06550: line 9, column 9: PLS-00302: component 'ANTAL' must be declared (antal=Quantity)

Answer 1

As noted above, you need to use := as the assignment operator. You also need a semi-colon after each statement - thus, you should use
then v_suffix := 'bil';
instead of
then v_suffix := 'bil'
So your code should look like:
declare
v_suffix varchar2(1);
begin
for o in (select bilägare_pnr, fnamn, enamn,
(select count(1)
from fordon
where fordon_pnr = bilägare_pnr) as bilar_ägda
from bilägare)
loop
if o.pnr_fordon = 1
then v_suffix := 'bil';
else v_suffix := 'bilar';
end if;
dbms_output.put_line(o.pnr || ', ' || o.fnamn || ', ' || o.enamn
|| ' Äger: ' || o.pnr_fordon || ' bil' || v_suffix);
end loop;
end;

Answer 2

Please try this piece of code:
begin
for rec in (select
o.id_nr || ',' || o.f_name || ',' || o.s_name || ', Owns: ' || coalesce(car.cnt, 0) || ' ' || decode(car.cnt , 1, 'Car', 'Cars') as res
from owners o
left outer join (select id_nr, count(1) as cnt from cars group by id_nr) car on (car.id_nr = o.id_nr)) loop
dbms_output.put_line(rec.res);
end loop;
end;
Thanks.

Answer 3

There are multiple issues in your code which is highlighted and fixed in following code:
declare
v_suffix varchar2(5); -- data length should be 5 or more
begin
for o in (select bilägare_pnr, fnamn, enamn,
(select count(1) from fordon where fordon_pnr = bilägare_pnr) as bilar_ägda
from bilägare)
loop
if o.bilar_ägda <= 1 -- replaced it from pnr_fordon and <= is used for 0 or 1 car
then v_suffix := 'bil'; -- := and ; is used here and in next statement
else v_suffix := 'bilar';
end if;
dbms_output.put_line(o.pnr || ', ' || o.fnamn || ', ' || o.enamn
|| ' Äger: ' || o.pnr_fordon || ' bil' || v_suffix);
end loop;
end;
/