Use sign () and decode () in Oracle to implement the IF-elseif-end Function

Create Table T8 (grade number (8); <br/> insert into T8 values (100); <br/> insert into T8 values (45 ); <br/> insert into T8 values (65); <br/> insert into T8 values (85); <br/> insert into T8 values (90 ); <br/> insert into T8 values (60); <br/> insert into T8 values (13); <br/> commit; </P> <p> select grade, decode (sign (grade-90 + 1), <br/> 1, 'A', <br/> decode (sign (grade-75 + 1 ), <br/> 1, 'B', <br/> decode (sign (grade-60 + 1 ), 1, 'C', 'D') <br/>) grade_char <br/> from T8 <br/> order by grade_char, grade; </P> <p> 13:43:36 select "> buffsms @ Testa> select grade, decode (sign (grade-90 + 1), <br/> 13:43:49 2 1, 'A', <br/> 13:43:49 3 decode (sign (grade-75 + 1), <br/> 13:43:49 4 1, 'B ', <br/> 13:43:49 5 decode (sign (grade-60 + 1), 1, 'C', 'D') <br/> 13:43:49 6) <br/> 13:43:49 7) grade_char <br/> 13:43:49 8 from T8 <br/> 13:43:49 order by grade _ Char, grade; </P> <p> grade gr <br/> -------------- -- <br/> 90 A <br/> 100 A <br/> 85 B <br/> 60 C <br/> 65 C <br/> 13 d <br/> 45 d </P> <p> you have selected 7 rows. </P> <p> used time: 00: 00: 00.00 <br/>