Select the correct answerWhat SQL statement is used to add a unique constraint to a column?OptionsUNIQUECHECKCONSTRAINTPRIMARY KEY

The correct answer is CONSTRAINT.

Here is how you can add a unique constraint to a column in SQL:

Step 1: First, you need to decide on which column you want to add a unique constraint. This column should not have duplicate values.

Step 2: Use the ALTER TABLE statement to modify the structure of the table.

Step 3: After the ALTER TABLE statement, write the name of the table.

Step 4: Use the ADD CONSTRAINT statement to add a unique constraint.

Step 5: After the ADD CONSTRAINT statement, write the name of the constraint.

Step 6: Use the UNIQUE keyword to specify that you are adding a unique constraint.

Step 7: In parentheses, write the name of the column to which you want to add the unique constraint.

Here is an example:

ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column_name);