No, you cannot use count
method in this situation. You have SQL nested table at hand, count
method is used only with PL/SQL collections.
To count number of nested table's elements you can either unnest that nested table or use scalar sub-query:
Unnesting:
SQL> select id
2 , count(*) as cnt
3 from test_table t
4 cross join table(t.cars_list)
5 group by id
6 ;
ID CNT
---------- ----------
1 2
Scalar sub-query:
SQL> select id
2 , (select count(column_value)
3 from table(t.cars_list)) as cnt
4 from test_table t
5 ;
ID CNT
---------- ----------
1 2