not equal to sign plsql code example

Example: plsql not equal

SELECT 1 FROM dual
WHERE 1 != 2
OR    1 <> 2;
-- WARNING: the not equal operators do NOT check for NULL value:
-- myTable: ID(CHAR) | flag(NUMBER)
-- 			A			1
-- 			B			0
-- 			C			NULL

SELECT ID FROM myTable t
WHERE t.flag != 1;
-- returns B

SELECT ID FROM myTable t
WHERE t.flag != 1 OR t.flag IS NULL;
-- returns B and C