anchor.diff:  
   <distinct_clause> ::= DISTINCT <distinct_spec>
   
  -<group_spec> ::= <or_column_name_list> [TOP <max_per_group>]
  +<execute_clause> ::= EXECUTE '(' function_name ((',' python_style_dict) | (',' key_value_pair)*) ')'
  +
  +<group_spec> ::= <comma_column_name_list> [TOP <max_per_group>]
   
   <distinct_spec> ::= <or_column_name_list>
   
   <or_column_name_list> ::= <column_name> ( OR <column_name> )*
  +
  +<comma_column_name_list> ::= <column_name> ( (OR | ',') <column_name> )*
   
   <limit_clause> ::= LIMIT [<offset> ','] <count>
   
  
positive.code: 
  <describe_stmt> ::= ( DESC | DESCRIBE ) [<index_name>]
  
  <select_list> ::= '*' | <column_name_list>
  
  <column_name_list> ::= <column_name> ( ',' <column_name> )*
  
  <from_clause> ::= FROM <index_name>
  
  
negative.code:                       | <limit_clause>
                        | <group_by_clause>
                        | <distinct_clause>
                        | <execute_clause>
                        | <browse_by_clause>
                        | <fetching_stored_clause>
                        | <route_by_clause>
  