oracle sql统计多个列
我想计算sql中具有特定值的列数。例如:oracle sql统计多个列,sql,oracle,aggregate-functions,Sql,Oracle,Aggregate Functions,我想计算sql中具有特定值的列数。例如: A B C D E 1 2 1 2 2 如何计算有3列的值为2 您可以使用decode进行此操作: Select decode(a, 2, 1, 0) + decode(b, 2, 1, 0) + decode(c, 2, 1, 0) + decode(d, 2, 1, 0) + decode(e, 2, 1, 0) from my_tab 备选用例: Select (case a when 2 then 1 else 0
A B C D E
1 2 1 2 2
如何计算有3列的值为2 您可以使用decode进行此操作:
Select decode(a, 2, 1, 0)
+ decode(b, 2, 1, 0)
+ decode(c, 2, 1, 0)
+ decode(d, 2, 1, 0)
+ decode(e, 2, 1, 0)
from my_tab
备选用例:
Select (case a when 2 then 1 else 0 end)
+ (case b when 2 then 1 else 0 end)
+ (case c when 2 then 1 else 0 end)
+ (case d when 2 then 1 else 0 end)
+ (case e when 2 then 1 else 0 end)
from my_tab
您可以使用“解码”来执行此操作:
Select decode(a, 2, 1, 0)
+ decode(b, 2, 1, 0)
+ decode(c, 2, 1, 0)
+ decode(d, 2, 1, 0)
+ decode(e, 2, 1, 0)
from my_tab
备选用例:
Select (case a when 2 then 1 else 0 end)
+ (case b when 2 then 1 else 0 end)
+ (case c when 2 then 1 else 0 end)
+ (case d when 2 then 1 else 0 end)
+ (case e when 2 then 1 else 0 end)
from my_tab
为了进一步理解Frank Schmitt的观点,您可以将“要计算的值”隐藏在内联表中,以避免重复:
Select
decode(a, countthis.countvalue, 1, 0)
+ decode(b, countthis.countvalue, 1, 0)
+ decode(c, countthis.countvalue, 1, 0)
+ decode(d, countthis.countvalue, 1, 0)
+ decode(e, countthis.countvalue, 1, 0)
from
my_tab
,(select 2 as countvalue from dual) countthis
为了进一步理解Frank Schmitt的观点,您可以将“要计算的值”隐藏在内联表中,以避免重复:
Select
decode(a, countthis.countvalue, 1, 0)
+ decode(b, countthis.countvalue, 1, 0)
+ decode(c, countthis.countvalue, 1, 0)
+ decode(d, countthis.countvalue, 1, 0)
+ decode(e, countthis.countvalue, 1, 0)
from
my_tab
,(select 2 as countvalue from dual) countthis