How to get the max record

Question

how to get the record with the max sequence no
table as
seq student mark
1 A 10
2 A 15
1 B 20
2 B 10
1 C 30
here is what i need
seq student mark
2 A 15
2 B 10
1 C 30

Answer 1

i have used your query + some decode
With t As
Select 'A' st, 'X' Type,    1 seq,   001 marker_no, 10 mark From dual Union All
Select 'A', 'X',    2,   001,       12 From dual Union All
Select 'B', 'X',    1,   002,       10 From dual Union All
Select 'B', 'X',    2,   003,       12 From dual Union All
Select 'B', 'X',    3,   003,       15 From dual Union All
Select 'C', 'X',    1,   001,       10 From dual Union All
Select 'C', 'X',    2,   002,       15 From dual Union All
Select 'C', 'Y',    3,   001,       20 From dual Union All
Select 'C', 'Y',    4,   001,       10 From dual
Select st,
       Sum (x_cnt) x_cnt,
       Max (x_seq) Keep (dense_rank Last Order By  x_seq) x_seq,
       max(x_marker_no) keep(dense_rank last order by x_seq) x_marker_no,
       max(x_mark) keep(dense_rank last order by x_seq) x_mark,
       sum(y_cnt) y_cnt,
       max(y_seq) keep(dense_rank last order by y_seq) y_seq,
       max(y_marker_no) keep(dense_rank last order by y_seq) y_marker_no,
       max(y_mark) keep(dense_rank last order by y_seq) y_mark
from
    (Select st,
           decode(Type ,'X',1,0) x_cnt,
           decode(type ,'X',seq,0) x_seq,
           decode(Type ,'X',marker_no,0) x_marker_no,
           decode(Type ,'X',mark,0) x_mark,
           decode(Type ,'Y',1,0) y_cnt,
           decode(Type ,'Y',seq,0) y_seq,
           decode(Type ,'Y',marker_no,0) y_marker_no,
           decode(Type ,'Y',mark,0) y_mark
      From t
Group By st;     
/*this is the output
st X_cnt X_seq X_marker_no X_mark Y_cnt Y_seq Y_marker_no Y_mark
A  2     2     001         12     0     null  null        null
B  3     3     003         15     0     null  null        null
C  2     2     002         15     2     4     001         10
ST      X_CNT      X_SEQ X_MARKER_NO     X_MARK      Y_CNT      Y_SEQ Y_MARKER_NO     Y_MARK
A           2          2           1         12          0          0           0          0
B           3          3           3         15          0          0           0          0
C           2          2           2         15          2          4           1         10