/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

2 votes248 views1 answer
Java.lang.arrayindexoutofboundsexception: index 0 out of bounds for length 0
SQL
1 vote229 views2 answers
Select only columns that are not empty oracle sql
SQL
4 votes249 views4 answers
Start mysql
SQL
0 vote223 views1 answer
Google sheets filter rows above current cell
SQL
6 votes256 views2 answers
Mysqldump password in file
SQL
0 vote236 views1 answer
Unique element in sql
SQL
12 votes264 views1 answer
Run mysql instance in docker
SQL
0 vote216 views2 answers
Sql select inside select
SQL
0 vote185 views1 answer
Connection error in mysql workbench
SQL
1 vote239 views1 answer
Copy postgres table from one schema into another
SQL