NLS_COMP and comparison

Question

Hello everyone,
Can someone explain me the impact of setting NLS_COMP to ANSI or LINGUISTIC on comparisons in SQL Statements?
In the documentation it is writen that:
"Comparisons for all SQL operations in the WHERE clause and in PL/SQL blocks should use the linguistic sort specified in the NLS_SORT parameter"
What would be the impact on changing NLS_COMP from BINARY to LINGUISTIC on the following query (assuming that col_a is of the type VARCHAR2):
SELECT * FROM table_a
WHERE col_a = :a
Best regards.
Carl

Answer 1

Hello Hans,
Thanks for this interresting URL reference.
I understand the effect of the NLS_SORT value on a sort.
What I was more curious about is the impact of the NLS_COMP value on WHERE clause of DML or Query staments.
In fact my collegue have just fond a good point:
If you have the following query:
SELECT * FROM tab_a
WHERE col_a > :a
Assuming that col_a is of the type VARCHAR2, NLS_COMP will have an impact.
So comparisons that involve ordering (<,>, <=, >=) always use the NLS_COMP value (and if it is set to ANSI or LINGUISTIC will also use the NLS_SORT value).
Is there any other cases someone can see?
Regards.
Carl