anchor.diff:  drop_database_encryption_key
       : DROP DATABASE ENCRYPTION KEY
       ;
  -    
  +
   // https://docs.microsoft.com/en-us/sql/t-sql/statements/drop-database-scoped-credential-transact-sql
   drop_database_scoped_credential
      : DROP DATABASE SCOPED CREDENTIAL credential_name=id
  
positive.code:     | IIF '(' cond=search_condition ',' left=expression ',' right=expression ')'   #IIF
      | STRING_AGG '(' expr=expression ',' separator=expression ')' (WITHIN GROUP '(' order_by_clause ')')?  #STRINGAGG
      ;
      
  xml_data_type_methods
      : value_method
      | query_method
  
negative.code: 
  file_size
      : DECIMAL( KB | MB | GB | TB | '%' )?
      ;
  