brackets to be used in COQL's Where.

brackets to be used in COQL's Where.

I use version 7 COQL to get Deals.
It seems that I need to properly enclose the criteria in brackets in the Where, but I don't know the criteria to enclose them.

I need to specify quite a few criteria in Where, so I would like a clear explanation.

I am not good at English.
I apologize if it is difficult to read.