SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    Identifier a3
    Identifier b3
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier tab2
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier tab3
     TableJoin (children 1)
      Function or (children 1)
       ExpressionList (children 2)
        Function equals (children 1)
         ExpressionList (children 2)
          Identifier a2
          Identifier a3
        Function equals (children 1)
         ExpressionList (children 2)
          Identifier b2
          Identifier b3
   ExpressionList (children 2)
    OrderByElement (children 1)
     Identifier a3
    OrderByElement (children 1)
     Identifier b3
