variables - SQL Server : Conditional where clause (Equal) OR (LessThan or Equal) -

where [date] <= case                        when @param = 1 convert(date, getdate())                    when @param = 2 dateadd(dd, 1, getdate()) 

the example above passes in variable @param intended filter for:

• @param = 1 (all days less or inclduing today).
• @param = 2 (all days less or inclduing today , tomorrow).
• @param = 3 (today only). requires change expression.

question

in sql server, how create conditional where clause evaluates different equality?

where [date] <=  [date] =   

or put way:

how can add filter today?

try:

where      ([date] <= convert(date,getdate()) , @param = 1) or     ([date] <= dateadd(dd, 1, getdate()) , @param = 2) or     ([date] = getdate() , @param = 3)