A. You can do this by converting the values to binary.
Assuming that you want to check a 4 character field to see if it has 'teST' in it (and you don't want to return values of 'test', 'TEST' etc.)
select * from <tbl>
where convert(varbinary(4), <col>) = convert (varbinary(4), 'teST')
To compare between tables
select * from <tbl1>, <tbl2>
where <tbl1.col> = <tbl2.col>
and convert(varbinary(4), <tbl1.col>) = convert (varbinary(4), <tbl2.col>)
The reason for having the two comparisons here is so that any indices will still be used. They won't be used just with a comparison that uses convert.