SQL Logic Operator Precedence: And and Or

And has precedence over Or, so, even if a <=> a1 Or a2

Where a And b 

is not the same as

Where a1 Or a2 And b,

because that would be Executed as

Where a1 Or (a2 And b)

and what you want, to make them the same, is

 Where (a1 Or a2) And b

Here's an example to illustrate:

Declare @x tinyInt = 1
Declare @y tinyInt = 0
Declare @z tinyInt = 0

Select Case When @x=1 OR @y=1 And @z=1 Then 'T' Else 'F' End -- outputs T
Select Case When (@x=1 OR @y=1) And @z=1 Then 'T' Else 'F' End -- outputs F