Question

I have two PLSQL Arrays of type nested table:

TYPE nested_typ IS TABLE OF VARCHAR2(21);

nt1 nested_typ := nested_typ('abc','def','123');
nt2 nested_typ := nested_typ('123');

I want to have the difference of these two collections, for above Ex: ‘def’, ‘abc’

Please suggest any simple way to do this?

Thanks…

Answer 1

These are simple types, so you can use PL/SQL’s set comparison operators. In your case you want to use MULTISET EXCEPT (works the same way as the SQL MINUS operator). Given a third nested table you would code something like:

nt3 := nt1 multiset except nt2;

Find out more.

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“This works fine when there are no duplicate elements in the array …
Is there any other way to remove all the occurrences of ‘123’ in the
nt1?”

Yes, use multiset except distinct.

There are lots of collection operators. As we would expect they are covered in the PL/SQL documentation. Find it here.