AlterQuery  mv (children 2)
 ExpressionList (children 1)
  AlterCommand MODIFY_QUERY (children 1)
   SelectWithUnionQuery (children 1)
    ExpressionList (children 1)
     SelectQuery (children 2)
      ExpressionList (children 2)
       Identifier a
       Identifier b
      TablesInSelectQuery (children 1)
       TablesInSelectQueryElement (children 1)
        TableExpression (children 1)
         TableIdentifier src_table
 Identifier mv
