NULL means missing/unknown/not available.
It isn't:
0 '' FALSE
And:
NULL = NULL
doesn't return TRUE.
Use:
IS NULL
or:
IS NOT NULL
Example:
WHERE manager_id IS NULL
SQL · NULL Handling & Data Types
What is NULL?
NULL means missing/unknown/not available.
It isn't:
0 '' FALSE
And:
NULL = NULL
doesn't return TRUE.
Use:
IS NULL
or:
IS NOT NULL
Example:
WHERE manager_id IS NULL
🎯 Put this concept into practice
Solidify this answer with real hands-on interview drills in the browser studio.