Purpose of "null is not null" and "null is null" statements

Hi all

Please can someone explain the purpose of these statements and what it means.

1 null is not null

2 null is null

(a) NULL should be treated in a special way in the comparisons - see values NULL SQL - IS NULL and IS NOT NULL or SQL ISNULL(), NVL(), IFNULL() and COALESCE() functions

(b) If you really clauses Null is not null or Null is null (meaning: the first is not a variable) it could replace "always wrong" and "always true"; Maybe in some test queries

Tags: Database

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