-- hold exclusive lock on MT4_USERS table
SELECT
u.*
FROM
TQueue q
INNER JOIN MT4_USERS u USING (LOGIN, REPORT_ID)
ORDER BY
u.ID ASC
FOR UPDATE;
-- insert to MT4_TRADES form TQueue ON DUPLICATE KEY UPDATE
INSERT MT4_TRADES (REPORT_ID, TICKET, LOGIN, SYMBOL, …)
SELECT
q.REPORT_ID, q.TICKET, q.LOGIN, q.SYMBOL, …
FROM
TQueue q
LEFT JOIN MT4_USERS mu USING(REPORT_ID, LOGIN)
ORDER BY
mu.ID ASC
ON DUPLICATE KEY UPDATE
LOGIN = VALUES(LOGIN)
,SYMBOL = VALUES(SYMBOL)
,DIGITS = VALUES(DIGITS)
,…FOR UPDATE
INSERT MT4_TRADES (REPORT_ID, TICKET, LOGIN, SYMBOL, …)
SELECT
q.REPORT_ID, q.TICKET, q.LOGIN, q.SYMBOL, …
FROM
TQueue q
LEFT JOIN MT4_USERS mu USING(REPORT_ID, LOGIN)
ORDER BY
q.ID ASC
FOR UPDATE
ON DUPLICATE KEY UPDATE
LOGIN = VALUES(LOGIN)
,SYMBOL = VALUES(SYMBOL)
,DIGITS = VALUES(DIGITS)
,…