update and insert statement in sql server

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SQL-Server

Hi I have question in sql server.

source table: emp

EmpId   |name   |Sdate       |checkvalue|deptno |deptname
1   |te |2015-09-18  |  2   |10 |Hr
1   |har    |2015-09-14  |  5   |10 |Pm
1   |ts |2015-08-13  |  2   |10 |ceo
1   |bu |2015-08-14  |  5   |10 |cm
1   |jai    |2013-04-21  |  5   |10 |pm
2   |kali   |2015-09-15  |  2   |20 |Deo
2   |hni    |2015-09-04  |  5   |20 |br
3   |jai    |2015-09-10  |  3   |20 |ceo
3   |man    |2015-09-16  |  5   |20 |hal
3   |tai    |2015-07-20  |  2   |20 |po
4   |han    |2013-05-08  |  2   |10 |kal

Target table : target emp:

testemp:
empId   |name   |Sdate       |checkvalue|deptno |deptname
1   |te |2015-09-18  |  2   |10 |Hr
1   |ts |2015-08-15  |  2   |10 |ceo
2   |kali   |2015-09-15  |  2   |20 |Deo
3   |tai    |2015-07-20  |  2   |20 |po
4   |jai    |2014-05-01   | 5   |10 |kal

here mainly focus checkvalue 2 with targetemp checkvalues5 and targetemp table checkvalues 2 with source side check values 5 :
1)checkvalue=5's sdate is less than or equal to checkvalue=2's sdate and
the difference between the dates should be less than 30days
2)if checkvalue=2 already exists in the target emp and new row is
checkvalues=5 then updated the follwing column checkvalue=2 from the
checkvalues=5(updated on the target table)
name column we need to update.
3)if checkvalues=5 already exists (on the target emp) and new row
is checkvalues=2 then update the following column on the existing checkvalues=5
(updated the targetemP table)
need to updated deptname column in the target emp table. if the condition not matched with target 2 values then need to insert 5 values in the target
similarly target 5 not matched condition then need to insert 2 values in the target.
based on above condition I want output in the targetemp table:

empId	|name	|Sdate	|checkvalue|deptno|deptname
1	|har	|2015-09-18 |	2	|10	|Hr ----updated
1	|bu	|2015-08-15 |	2	|10	|ceo ------updated
1	|jai	|2013-04-21 |	5	|10	|pm ------inserted
2	|hni	|2015-09-15 |	2	|20	|Deo-------updated
3	|tai	|2015-07-20 |	2	|20	|po
3	|man	|2015-09-16 |	5	|20	|hal-----inserted
4	|jai	|2014-05-01 |	5	|10	|kal
4	|han	|2013-05-08 |	2	|10	|kal----inserted
5 |ope |2015-02-10 | 2 |10 |te -----updated
5 |b |2015-02-09 | 2 |10 |t

I tried for update statement like below:

update targetemp 
set name = o.name
from emp o 
join targetemp t on o.empid = t.empid 
and o.deptno = t.deptno 
and o.checkvalue in ('5') 
and t.checkvalue in ('2') and o.sdate <= t.sdate
and datediff(dd, o.sdate, t.sdate) <= 30 
and t.sdate = (select max(t.sdate) 
from empo 
join targetemp t on o.empid = t.empid 
and o.deptno = t.deptno 
and o.checkvalue in ('5') 
and t.checkvalue in ('2') 
and o.sdate <= t.sdate 
and datediff(dd, o.sdate, t.sdate) <= 30)

but it did not given expect result.please tell me how to write query achive this task in sql server .