correct answerWhat is the SQL keyword used to specify that a column can contain NULL values?OptionsNOT NULLNULL ABLEALLOW NULLWITH NULLS

Which is the SQL constraint that allows inputting NULL in a specified column in a DBMS table but that does not allow inputting the already entered value?

What is the purpose of the NULL value in SQL? *It represents an empty string.It represents a missing or unknown value.It represents the absence of a primary key.It represents a zero value.

In SQL, which operator is used to check if a value is within a specified range?OptionsINLIKEIS NULLBETWEEN

A NOT NULL __________ is a rule that prevents certain fields in a database from being left blank.answerscalabilityschemaquery builderconstraint

Select the correct answerWhich SQL constraint do we use to set some value to a field whose value has not been added explicitly?OptionsNOT NULLUNIQUEDEFAULTCHECK