>I have two issues relating to SQL Server:
>(1) Can the column name assigned by the AS CLAUSE be used in the WHERE CLAUSE of a SQL Statement ?

No. It can only be used in ORDER BY clause.

>(2) When using "$" in VFP, you can have
> (a) MYFIELDNAME $ MYSTRING or
> (b) MYSTRING $ MYFIELDNAME.
> Can the the LIKE command in SQL Server achieve the same results as above ?

You can but it could be slow on big tables.

... MYFIELDNAME Like ('%' +  MYSTRING + '%') Or
    MYSTRING Like  ( '%' + MYFIELDNAME + '%')