In case you have your own slow SQL query, you can optimize it automatically here.
For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:
CREATE INDEX tbltarget_idx_sd_custid_rate ON tblTarget (SD,custId,Rate);
SELECT
s.SD,
s.UpdateDate,
s.CustId,
s.Period,
s.Rate
FROM
tblScource s
LEFT JOIN
tblTarget t
ON t.sd = s.SD
AND s.CustId = t.CustId
AND s.Period = t.Rate
WHERE
t.SD IS NULL
AND t.custId IS NULL