SQL equivalent of Math.Floor() in c#

I just want to convert 10.111 to 10 based on some condition in the following Query

Select 
    case when 2=1 then
        CONVERT(de开发者_开发知识库cimal(10,3), 10.111)
    else
        CONVERT(decimal(10,0), 10.111)
    end

But it return 10.000 How can i get 10?

The CASE expression as a whole must all evaluate to the same datatype. The only way of having one branch evaluate to decimal(10,3) and the other to a different datatype would be to do a cast to sql_variant

Select 
    case when 2=1 then
        CONVERT(decimal(10,3), 10.111)
    else
        CAST(FLOOR( 10.111) AS SQL_VARIANT)
    end