How to write Nested Query in CAML

It's strange that CAML query can only compare a pair of expressions either by <And> or <Or>. So if you have a query like you want to filter <And> condition between two <Or> condition, then you need to use nested <And> or <Or>, in which each operator only takes two expressions. This will make things more complicate especially for a number of conditions mixed with <And> and <Or>.

Example :

<Query>

   <Where>

      <And>

         <Geq>

            <FieldRef Name="Expires" />

            <Value Type="DateTime"><Today/>Value>

         </Geq>

      <Or>

         <Eq>

            <FieldRef Name="SubCategory" />

            <Value Type="Choice">PreLoginValue>

         </Eq>     

         <Eq>

            <FieldRef Name="SubCategory" />

            <Value Type="Choice">BothValue>

         </Eq>

      </Or>

    </And>

   </Where>

</Query>

Thanks.

Special Thanks to Mr.Abhay Wad.