This is the description of the document：
Here's my setup：
ALTER SESSION SET NLS_COMP = 'BINARY';
ALTER SESSION SET NLS_SORT = 'BINARY_CI';
Therefore, according to the description in the documentation, the operation of the DISTINCT depends on the result of NLS_SORT.
But here are my test results.
select ID,
NAME,
NLSSORT(NAME),
count(DISTINCT NAME) over ()
from (select ID, NAME from T200_12_FRENCH where NAME = 'E' or NAME = 'É' or NAME = 'e' or NAME = 'é');
results:
I understand that the result of the count function should be the result of NLSSORT(NAME) deduplication: 2. However, the execution result is 4.