SQL

how to add not null constraint in sql

ALTER TABLE table_name MODIFY column_name datatype NOT NULL;

sql not null

SELECT column_name FROM table_name 
WHERE column_name IS NOT NULL;

add not null constraint sql server

ALTER TABLE table1 ALTER COLUMN column1 datatype NOT NULL;

sql is not null

SELECT * FROM my_table WHERE my_column IS NOT NULL;

SQL NOT NULL Constraint

CREATE TABLE Colleges (
  college_id INT NOT NULL,
  college_code VARCHAR(20),
  college_name VARCHAR(50)
);

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
);

SQL NOT NULL Constraint

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255) NOT NULL,
    Age int
);

sql is not null

The reverse of NULL. Tests for values that aren’t empty / NULL
"Tests for empty (NULL) values.
Example: Returns users that haven’t given a contact number.
SELECT * FROM users
WHERE contact_number IS NULL;"

is not null sql

select c_custkey, c_name, c_address from customer where c_custkey in (select o_orderkey from orders where o_orderkey IS NOT NULL)

not null constraint

ID int(10) NOT NULL;

SQL NOT NULL Constraint

CREATE TABLE Colleges (
  college_id INT NOT NULL,
  college_code VARCHAR(20) NOT NULL,
  college_name VARCHAR(50)
);