Example 2-27 Using a Search Condition With a CASE Statement

DECLARE
   grade CHAR(1) := 'B';
   appraisal VARCHAR2(120);
   id NUMBER := 8429862;
   attendance NUMBER := 150;
   min_days CONSTANT NUMBER := 200;
FUNCTION attends_this_school(id NUMBER) RETURN BOOLEAN IS
   BEGIN RETURN TRUE; END;
BEGIN
   appraisal :=
      CASE
         WHEN attends_this_school(id) = FALSE THEN 'N/A - Student not enrolled'
-- Have to test this condition early to detect good students with bad attendance
         WHEN grade = 'F' OR attendance < min_days 
            THEN 'Poor (poor performance or bad attendance)'
         WHEN grade = 'A' THEN 'Excellent'
         WHEN grade = 'B' THEN 'Very Good'
         WHEN grade = 'C' THEN 'Good'
         WHEN grade = 'D' THEN 'Fair'
         ELSE 'No such grade'
      END;
   DBMS_OUTPUT.PUT_LINE('Result for student ' || id || ' is ' || appraisal);
END;
/