挑選同列最大與最小

ORACLE SQL 挑選同列最大與最小

SQL> select * from t2;

A                    B                    C                    D
-------------------- -------------------- -------------------- ------
1111                 1                    1                    1
2222                 1                    1                    2
3333                 2                    1                    1
4444                 2                    2                    1
5555                 2                    2                    2

SQL> select greatest(a,b,c,d), least(a,b,c,d) from t2;

GREATEST(A,B,C,D)    LEAST(A,B,C,D)
-------------------- --------------------
1111                 1
2222                 1
3333                 1
4444                 1
5555                 2