/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

3 votes246 views4 answers
Mysql create table from select statement
SQL
0 vote196 views1 answer
Sqlite select split string
SQL
0 vote244 views2 answers
Homebrew nysql launch
SQL
-1 vote202 views3 answers
SQL to LINQ converter
SQL
3 votes196 views1 answer
Oracle user quota unlimited
SQL
0 vote251 views2 answers
Mysql add days to date
SQL
10 votes193 views1 answer
Oracle view dependencies
SQL
9 votes189 views1 answer
Mysql check date range
SQL
7 votes192 views6 answers
Reset identity column in sql server
SQL
3 votes149 views1 answer
How to get list of synonyms in oracle
SQL