SQL CHECK Keyword

❮ SQL Keywords

constraint limits the value that can be placed in a column.

The following SQL creates a CHECK constraint on the "Age" column when the "Persons" table is created. The CHECK constraint ensures that you can not have any person below 18 years:

( Age int, CHECK (Age>=18)

( Age int CHECK (Age>=18)

To allow naming of a CHECK constraint, and for defining a CHECK constraint on multiple columns, use the following SQL syntax:

( Age int, City varchar(255), CONSTRAINT CHK_Person CHECK (Age>=18 AND City='Sandnes')

To create a CHECK constraint on the "Age" column when the table is already created, use the following SQL:

To allow naming of a CHECK constraint, and for defining a CHECK constraint on multiple columns, use the following SQL syntax:

To drop a CHECK constraint, use the following SQL:

❮ SQL Keywords