SQL Script to compareof two or more tables

I need a SQL script to compare the values in Table A with the Values in Table B. If the value in Table A is not found in Table B return the values of Table A. I'm sure there is a easy way to do this but being a novice I need some Help.
Thanks in advance

Do You mean those records which are in table A but not in TableB, then this code should work
SELECT t1.* FROM TableA t1 LEFT JOIN TableB t2 ON YourConditions
WHERE t2.col IS NULL