IN Clause with NULL or IS NULL

Question

Postgres is the database

Can I use a NULL value for a IN clause? example:

SELECT *
FROM tbl_name
WHERE id_field IN (\'value1\', \'value2\', \'value3\         


        

Answer 1

Null refers to an absence of data. Null is formally defined as a value that is unavailable, unassigned, unknown or inapplicable (OCA Oracle Database 12c, SQL Fundamentals I Exam Guide, p87). So, you may not see records with columns containing null values when said columns are restricted using an "in" or "not in" clauses.