File Extension WDT File Format WinSQL schema diff template file WDT stands for WinSQL schema diff template file. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question How to block AS/400 users from using WinSQL what is the diff between cursor and plsql table SETON LR and RETURN.