SQL Keywords: NULL

The NULL keyword is used in SQL operations. It can be used when creating a column to indicate that the column can hold null values. Here is an example:

CREATE TABLE Contractors(FirstName TEXT NULL);

To negate the NULL keyword in this case, precede it with NOT to get NOT NULL. Here is an example that creates a columns and specifies that the column cannot hold null values:

CREATE TABLE Contractors(FirstName TEXT NULL,
                         LastName VARCHAR NOT NULL);