PLS-00570
different number of columns in the multiset and cast expressions
Cause
Number of columns in the collection returned by MULTISET and the number of columns for the CAST type don't match. For example: create type tab_obj as object (n number); create type tab1 as table of tab_obj; create table tab2 (col1 number, col2 number); select CAST(MULTISET(select col1, col2 from tab2) as tab1) from tab2;