/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 vote347 views2 answers
Sqlite unix timestamp
SQL
5 votes352 views1 answer
Postgres integer to serial
SQL
-1 vote330 views2 answers
REMOVE DATE FROM DATE TIME SQL SERVER
SQL
2 votes343 views1 answer
Columns Present in a table
SQL
0 vote345 views1 answer
Default value false mysql
SQL
12 votes348 views6 answers
Between in sql
SQL
9 votes382 views2 answers
Convert data type in sql
SQL
4 votes327 views1 answer
Oracle change nls_date_format permanently
SQL
0 vote342 views1 answer
Mysql import datetime YYYY-MM-DDThh:mm:ss.000000Z
SQL
3 votes329 views1 answer
Search for column name in psql
SQL