CASE

WHEN condition_1 THEN statements_1

WHEN condition_2 THEN statements_2

...

WHEN condition_n THEN statements_n

[ ELSE

    else_statements ]

END CASE;]

DECLARE

    grade CHAR(1);

BEGIN

    grade := 'B';

    CASE

        WHEN grade = 'A' THEN DBMS_OUTPUT.PUT_LINE('优秀');

        WHEN grade = 'B' THEN DBMS_OUTPUT.PUT_LINE('良好');

        WHEN grade = 'C' THEN DBMS_OUTPUT.PUT_LINE('好');

        WHEN grade = 'D' THEN DBMS_OUTPUT.PUT_LINE('及格');

        WHEN grade = 'F' THEN DBMS_OUTPUT.PUT_LINE('不及格');

        ELSE DBMS_OUTPUT.PUT_LINE('没有该等级');

    END CASE;

END;

DECLARE

    grade CHAR(1);

BEGIN

    grade := 'M';

    CASE

        WHEN grade = 'A' THEN DBMS_OUTPUT.PUT_LINE('优秀');

        WHEN grade = 'B' THEN DBMS_OUTPUT.PUT_LINE('良好');

        WHEN grade = 'C' THEN DBMS_OUTPUT.PUT_LINE('好');

        WHEN grade = 'D' THEN DBMS_OUTPUT.PUT_LINE('及格');

        WHEN grade = 'F' THEN DBMS_OUTPUT.PUT_LINE('不及格');       

    END CASE;

EXCEPTION

    --使用异常处理来替代CASE语句中的ELSE子句

    WHEN CASE_NOT_FOUND THEN

        DBMS_OUTPUT.PUT_LINE('没有该等级');

END;