Standard Request Handler Boosting

[Sujatha Arun]

I want to know  what is the difference between the normal Boosting and
boosting using functionQuery for the standard request handler

In the example below I want to boost the field 2 with higher influence on
score
Example:

 field1:<query value> field2:<query value>^boost value

Example  :

 field1<query value> AND _val_:"<field2>"^boost value

Regards
Sujatha