What's null value?

Answer 1

//for SQL [from a lesson I made earlier]
we use null value when the value is not known or meaningless.
A column is said to contain a null if no value is assigned to that column .

Any column of any datatype of a table can contain null provided they are not restricted by PRIMARY KEY or NOT NULL as the integrity constraints .

example -
CREATE TABLE class(rollno int primary key, marks int, sname varchar(30) not null);

while inserting records in the table class using INSERT statement , only marks column can be omitted , if any column other than marks is skipped or omitted than error message will appear that record is not added
example-
INSERT INTO class(rollno,marks) VALUES(10111,9);
//error message will be displayed because sname column can't have null value

//☺👍

Answer 2

Null = nothing, no value.

Answer 3

Sorry I am joining today app it's OK I tried to leaning sql thanks