sql语句优化,可以用decode实现吗

[angel089]

select 1,
' less than 1 minute' During,
count(*) as Num,
count(*) / 45637 * 100 as Percentage
from al_history
where clear_during < 60
union
select 2,
'1-5 minute' During,
count(*) as Num,
count(*) / 45637 * 100 as Percentage
from al_history
where clear_during >= 60
and clear_during < 300
union
select 3,
'5-10 minute' During,
count(*) as Num,
count(*) / 45637 * 100 as Percentage
from al_history
where clear_during >= 300
and clear_during < 600
union
select 4,
'more than 10 minutes' During,
count(*) as Num,
count(*) / 45637 * 100 as Percentage
from al_history
where clear_during >= 600

[mantisXF]

可以。 :)

[angel089]

该怎么写呢

[mantisXF]

这个嘛 。。。 嘿嘿！！

[angel089]

哎，

[mantisXF]

-- TRY IT ...  下次带多点分会更多人帮你：
SELECT SID,
       DURING,
       COUNT(1) "NUM",
       COUNT(1)/4563700 "PERCENTAGE"
  FROM (      
       SELECT (CASE WHEN CLEAR_DURING < 60
                      THEN 1
                    WHEN CLEAR_DURING >= 60 AND CLEAR_DURING < 300
                      THEN 2
                    WHEN CLEAR_DURING >= 300 AND CLEAR_DURING < 600
                      THEN 3
                    WHEN CLEAR_DURING >= 600
                      THEN 4
                    ELSE 0
                END) "SID",
              (CASE WHEN CLEAR_DURING < 60
                      THEN 'LESS THAN 1 MINUTE'
                    WHEN CLEAR_DURING >= 60 AND CLEAR_DURING < 300
                      THEN '1-5 MINUTE'
                    WHEN CLEAR_DURING >= 300 AND CLEAR_DURING < 600
                      THEN '5-10 MINUTE'
                    WHEN CLEAR_DURING >= 600
                      THEN 'MORE THAN 10 MINUTES'
                    ELSE 0
                END) "DURING"
         FROM AL_HISTORY
        )TT
 GROUP BY SID,DURING;

[kingofworl]

你这么写就行 也可以用case when

[angel089]

已经实现了，用case实现的，呵呵！谢谢啦