How to use if at SAP HANA

I need to convert an old Crystal Report to run on HANA and I'm with the following problem.

The query is executed in accordance with the if below:

declare @var1 int
set @var1 = {?DataType}
if @var1 = 1 -- runs query 1 if the user chooses 1
begin  --query1
end
else -- runs query2 if the user chooses 2
begin  --query2
end

It seems that HANA doesn't support this type if structure.

Is there another way to get the same result?