UPDATE with ORDER BY and LIMIT not working in MYSQL

Salam You can use this method and work properly !

UPDATE Ratemaster, Rates 
SET Ratemaster.Rate=Rates.Rate 
WHERE Ratemaster.user=Rates.user 
ORDER BY Rates.id
LIMIT 1

Read article about How to use ORDER BY and LIMIT on multi-table updates in MySQL

For the multiple-table syntax, UPDATE updates rows in each table named in table_references that satisfy the conditions. In this case, ORDER BY and LIMIT cannot be used.

Usually you can use LIMIT and ORDER in your UPDATE statements, but in your case not, as written in the MySQL Documentation 12.2.10. UPDATE Syntax:

For the multiple-table syntax, UPDATE updates rows in each table named in table_references that satisfy the conditions. In this case, ORDER BY and LIMIT cannot be used.

Try the following:

UPDATE Ratemaster
SET Ratemaster.Rate =
(
    SELECT Rates.Rate
    FROM Rates
    WHERE Ratemaster.user = Rates.user
    ORDER BY Rates.id
    LIMIT 1
)

Work It 100%

UPDATE table  SET Sing='p'  ORDER BY sr_no  LIMIT 10;