Does "WHERE 1=1" usually have an impact on query performance? I recently saw the question "where 1=1 statement"; a SQL construct I have used often in constructing dynamic SQL in an effort to write cleaner code (from the perspective of the host language).

Generally speaking, does this addition to a SQL statment negatively affect query performance? I'm not looking for an answer in regard to a specific database system (because I have used it in DB2, SQL Server, MS-Access, and mysql)-- unless it's impossible to answer without getting into specifics.
All the major RDBMS, as far as I know, have built in constant evaluations.  This should evaluate pretty much instantaneously in any of them.