If statement to get different attributes - fetchXML

Question

Using SQL as example, is it possible to have a "if select" statement in FetchXML to get different attributes depending on a condition?

For example, if @value=1 , fetch attributes "a" and "b", else, fetch attributes "c" and "d".

I am new to this.

Answer 1

Whatever it is, SQL or fetchXML in js/C# or any other technology/software, the only way to achieve this requirement is - Dynamic query technique. Compose the query in string the way we want & execute the string query in runtime.

For example:

string query =  @"
   <fetch mapping='logical'>
     <entity name='contact'>";

if (value == 1)
{
        query+= "<attribute name='title'/> 
                 <attribute name='fullname'/>";
}
else
{
        query+= "<attribute name='firstname'/> 
                 <attribute name='lastname'/>";
}

     query+= "</entity> 
            </fetch>";