title: When creating a table using SQL, a variable student-type can be either post-grad or under-grad. What data type should I use?
body: <p>This is what I have now. I have done a check for DECIMAL() using BETWEEN AND. Was wondering if it is possible to do the same for VARCHAR()</p>
  
  <pre><code>CREATE TABLE STUDENT(
  student_number      CHAR(4)         NOT NULL,
  first_name          VARCHAR(50)     NULL,
  last_name           VARCHAR(50)     NULL,
  date_of_birth       DATE            NULL,
  student_type        VARCHAR(20)     NULL,
  CONSTRAINT student_pkey PRIMARY KEY (student_number),
  CONSTRAINT student_check1 CHECK (student_type POSTGRADUDATE_STUDENT OR UNDERGRADUATE_STUDENT));
  </code></pre>