/SQL/How to add not null constraint in sql

How to add not null constraint in sql

ALTER TABLE table_name MODIFY column_name datatype NOT NULL;

Source: tutorialspoint.com

NOT NULL SQL

By default, a column can hold NULL values.
The NOT NULL constraint enforces a column to NOT accept NULL values.
This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.

Sql NOT NULL in creating a table
CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255) NOT NULL,
    Age int
);

Similar codes

0 vote203 views1 answer
Psql no such file or directory
SQL
7 votes185 views4 answers
How to reset the identity column in sql server
SQL
3 votes208 views4 answers
Psql list tables in schema
SQL
23 votes150 views3 answers
Mysqldump
SQL
11 votes206 views2 answers
Set default column value sql
SQL
0 vote201 views1 answer
Sql waitfor
SQL
0 vote191 views1 answer
Sum sqlserver
SQL
3 votes179 views1 answer
Only join in sql
SQL
11 votes215 views2 answers
Sql rank
SQL
0 vote181 views1 answer
Sql how to get courses that i have made prerequisites
SQL