SQL服务器中的查找模式

Question

I have the below query which returns me the mode which is the most repeated value in a data set

select top 1 TargetPriceRec as mode 
from PricingRecurring  
Group By TargetPriceRec order by Count(*) desc

I get the most repeated value from this but the issue is that if there is no repeated value I am still getting the highest value in the dataset. How can I get an empty value if there are no repeating values in the dataset and also if there are multiple repeating values I still get an empty value since there is no single mode.

Any help is much appreaciated.

Thanks

Answer 1

You can get all the modes using:

select top (1) with ties TargetPriceRec as mode 
from PricingRecurring  
Group By TargetPriceRec
order by Count(*) desc;

For your desired results:

select (case when count(*) = 1 then max(TargetPriceRec) end) as mode
from (select top (1) with ties TargetPriceRec 
      from PricingRecurring  
      Group By TargetPriceRec
      order by Count(*) desc
     ) m