Merge data when inserting into another table with the same ID - sql-server

Question

I have a table with the following data, the lab_sample_id are identical, I’m inserting this data into another table. I would like to merge the data when inserting into another table if the lab_sample_id is the same for leg_id 1 and 3.
leg_id 1 & 3 will always have unique data but the lab_sample_id might be identical.
Here's my current code:
INSERT INTO SAMPLE_RESULT
(PPK, LAB_SAMPLE_ID, LEG_ID, PT, PT_METHOD,
PT_MIN_DETECTION, CU, CU_METHOD, CU_MIN_DETECTION)
SELECT B.PK, CSR.LAB_SAMPLE_ID, CSR.LEG_ID, CSR.PT, CSR.PT_METHOD,
CSR.PT_MIN_DETECTION, CSR.CU, CSR.CU_METHOD, CSR.CU_MIN_DETECTION
FROM [SOURCE] S
JOIN CLEARING_BATCH CB ON CB.PPK = S.PK
JOIN CLEARING_SAMPLE_RESULT CSR ON CSR.PPK = CB.PK
JOIN SAMPLE_REG SR ON SR.FIELD_SAMP_ID = CSR.LAB_SAMPLE_ID
LEFT JOIN PROSPECTS_AND_MINES PM ON PM.PPK = S.PK
LEFT JOIN LABORATORY L ON L.PPK = PM.PK
LEFT JOIN BATCH B ON L.PK = B.PPK
WHERE CB.PK =#Submission_Pk
AND CB.BATCH_ID = B.BATCH_ID
AND NOT EXISTS(SELECT *
FROM SAMPLE_RESULT SR
WHERE SR.PPK = B.PK
AND SR.LAB_SAMPLE_ID = CSR.LAB_SAMPLE_ID
AND SR.LEG_ID = CSR.LEG_ID)

Answer 1

Something like this should do the trick, where you can JOIN the table to itself:
SELECT t1.LAB_SAMPLE_ID,
t1.LEG_ID,
t1.PT,
t1.PT_METHOD,
t1.PT_MIN_DETECTION,
t2.cu,
t2.CU_METHOD,
t2.CU_MIN_DETECTION
FROM CLEARING_SAMPLE_RESULT t1
INNER JOIN CLEARING_SAMPLE_RESULT t2
ON t1.LAB_SAMPLE_ID = t2.LAB_SAMPLE_ID
WHERE t1.LAB_SAMPLE_ID = 1 AND t2.LAB_SAMPLE_ID = 3
Then you can modify your UPDATE logic to use this data.