query revisions an vigilant graph

i'm implementing an review record database, all createdat removedat column. i wish means list revisions an vigilant graph nonetheless best proceed i cruise unions. i need each unparalleled createdat removedat id.

if i'm removing list countries provinces kinship looks this:

select c.createdat revisionid countries c where localid=@country
union
select p.createdat revisionid provinces p 
inner join countries c p.countryid=c.localid c.localid = @country
union
select c.removedat revisionid countries c where localid=@country
union
select p.removedat revisionid provinces p 
inner join countries c p.countryid=c.localid c.localid = @country

for some-more difficult queries definitely difficult presumably perform unequivocally feeble i wanted anyone cruise improved approach. mssql server.

i need unparalleled list since being used apportionment genuine information comes fasten this.