Specifies a condition that controls how many times SQL can
    execute the statements embedded within its REPEAT . . . UNTIL
    block (collectively referred to as its compound statement). SQL
    executes the compound statement once and then evaluates the UNTIL
    condition. If it evaluates to false or NULL (unknown) and does
    not encounter an error exception, SQL executes the compound
    statement again. Each time the search condition evaluates
    to false or NULL, the REPEAT statement executes the compound
    statement. If the UNTIL condition evaluates to true, SQL bypasses
    the compound statement and passes control to the statement after
    the END REPEAT statement.