Does the NULL value match with 0 or space values in the database? What are their data types?

In a database, the value NULL does not match 0 or a space.

• NULL is a special value indicating the absence of data or an unknown value. It is not equal to any other value, including 0 or an empty string.
• 0 is a numeric value, with the data type depending on the column (for example, INTEGER).
• A space is a character, part of a string value, usually of data types VARCHAR or CHAR.

For example, in SQL, the expression NULL = 0 returns FALSE, and NULL = NULL also returns FALSE because NULL cannot be directly compared. To check for NULL, use IS NULL.