SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier a1 (alias a)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier a2 (alias b)
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier a.a
        Identifier b.a
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier b
   Set
