What is the use of where keyword in sql

Answer 1

where is use for selection of data.
suppose there is an attribute having name and rollno.
then when you want to access the detail of roll no 5
you can access as
select * from table
where rollno = 5;

Answer 2

SELECT * FROM users WHERE age >= 21;

Basically, select everything from the users table WHERE age is greater than or equals 21.

Answer 3

where keyword is used to select or fetch the information or records from a table