Select and Insert rows that have changed - sql

Question

I have the following query:
select z.EncID, z.PatName, convert(datetime,z.ArriveDtTm) ArriveDtTm,
z.Status, convert(datetime,z.UpdateTime) UpdateTime
from
OPENQUERY(linked_db, '
select e.encntr_id as EncID, p.name_full_formatted as PatName,
e.arrive_dt_tm as ArriveDtTm , e.referring_comment as Status,
e.updt_dt_tm as UpdateTime
from
TRACKING_CHECKIN TC,
encounter e,
tracking_item ti,
person p
where
tc.checkin_dt_tm >= sysdate-1
and TC.TRACKING_GROUP_CD= 5328362.00
and ti.tracking_id = tc.tracking_id
and ti.encntr_id = e.encntr_id
and e.disch_dt_tm is null
and e.person_id = p.person_id
and e.loc_nurse_unit_cd = 664926.00
order by e.arrive_dt_tm, e.disch_dt_tm desc'
)z
I want to take the results and insert into another table if the rows is different in any way. What is the best way to accomplish?
The code will be in a job that runs every 5 minutes.
thanks

Answer 1

Use SQL server Merge for SQL 2008+, or fall back to manual insert and update for lower versions of SQL as shown in the query.
Note : It is just a quick query. It was not validated against data.
SELECT z.encid,
z.patname,
CONVERT(DATETIME, z.arrivedttm) ArriveDtTm,
z.status,
CONVERT(DATETIME, z.updatetime) UpdateTime
INTO #temp_table
FROM Openquery (linked_db, 'Link Query') AS z;
/****************** USING MERGE For SQL 2008+ ********************/
MERGE destinationtable A USING #temp_table B ON A.encid= b.encid WHEN matched THEN
UPDATE
SET A.patname = B.patname,
A.arrivedttm = B.arrivedttm,
A.status= B.status WHEN NOT matched THEN
INSERT (encid,
patname,
arrivedttm,
status)
VALUES (b.encid,
b.patname,
b.arrivedttm,
b.status) END
SELECT * FROM destinationtable ;
/***************** Without MERGE For SQL 2000 *******************/
-- Insert Part
INSERT INTO destinationtable (encid, patname, arrivedttm, status)
SELECT Col1,
Col2
FROM #temp_table A
LEFT JOIN destinationtable B ON A.encid = B.encid
WHERE B.encid IS NULL
-- Update Part
UPDATE A
SET A.patname = B.patname,
A.arrivedttm = B.arrivedttm,
A.status= B.status
FROM destinationtable A
INNER JOIN #temp_table B ON A.encid = B.encid
SELECT * FROM destinationtable ;
/*****************************************************************/