Oracle 查询优化无子查询

Question

I am looking to make my query more optimized and simpler. I have to fetch only those T_ID's whose score is maximum and if that T_ID has a Msg 'C' then it should not be included.

My data looks like:

My Query is:

SELECT DISTINCT T_ID, Msg, MAX(Score) over (Partition by T_ID)
FROM Sample
WHERE T_ID NOT IN (SELECT T_ID FROM Sample WHERE Msg = 'C');

My Answer is:

Is there any way to achieve this by calling the database only once.

Answer 1

Tip #1: Images are not conducive to building a test case with your data:-(

But you could do something like this, assuming "0" is a suitable boundary (or perhaps -1)

SQL> with t as (
  2    select 77 t_id, 'N' msg, 220 score from dual union all
  3    select 77 t_id, 'C' msg, 220 score from dual union all
  4    select  1 t_id, 'N' msg, 120 score from dual union all
  5    select  1 t_id, 'N' msg, 102 score from dual union all
  6    select  2 t_id, 'N' msg, 112 score from dual union all
  7    select  2 t_id, 'C' msg, 152 score from dual union all
  8    select  3 t_id, 'N' msg, 172 score from dual union all
  9    select  3 t_id, 'N' msg, 192 score from dual union all
 10    select  4 t_id, 'N' msg, 100 score from dual union all
 11    select  5 t_id, 'N' msg, 101 score from dual
 12  )
 13  select t_id, max(score)
 14  from t
 15  group by t_id
 16  having min(decode(msg,'C',0,score)) > 0;

      T_ID MAX(SCORE)
---------- ----------
         1        120
         4        100
         5        101
         3        192