Question

I want to make a query using a conditional to select a clause for filter.
Something like this.

SELECT Id,name,last_name,submitDate,lastvisitDate 
from Visitor Where if(submitDate is not null) begin submitDate >= @dateFrom end
and if(submitDate is not null) begin submitDate < @dateTo end

but I need for example if @dateTo is null this variable doesn’t participate on the filter query

Answer 1

You can apply ISNULL to @dateTo and thus default it to some really distant future date, like 30000101:

…
WHERE submitDate IS NULL
   OR submitDate >= @dateFrom AND submitDate < ISNULL(@dateTo, '30000101')