How to insert blank value not NULL using mysql query

Answer 1

For varchar type you can just give two doubles quotes and it will do.
Not sure about other data types.

Answer 2

Please add SQL to your question tags to improve context clarity and prevent misunderstanding 👍

Your question is a bit vague, you didn't mention the type of the said column, also whether if it was created with/without NULL option specified.

(Edit)
Question edited, NULL option specified (not acceptable).

If it was a VARCHAR family, you may use '' (adjacent single quotes - an empty string), and if it accepts null you can use NULL (no quotes, all caps).

Hth, cmiiw