SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Identifier columns
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.query_log
   Function and (children 1)
    ExpressionList (children 3)
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier initial_query_id
       Subquery (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 4)
           ExpressionList (children 1)
            Identifier query_id
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              TableIdentifier system.query_log
           Function and (children 1)
            ExpressionList (children 2)
             Function equals (children 1)
              ExpressionList (children 2)
               Identifier current_database
               Function currentDatabase (children 1)
                ExpressionList
             Function equals (children 1)
              ExpressionList (children 2)
               Identifier log_comment
               Literal \'THIS IS A COMMENT TO MARK THE INITIAL QUERY\'
           Literal UInt64_1
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier type
       Literal \'QueryFinish\'
     Function not (children 1)
      ExpressionList (children 1)
       Identifier is_initial_query
