mysql return two minimum values with limit - mysql

Question

I have a table named: workers and a table named: schedule with the following format:
workers:
| id | name | vacationA | vacationB | workhistory |
| 1 | Florin | 2017-05-05 | 2017-05-25 | 2010-01-01 |
| 2 | Andrei | 2017-06-05 | 2017-06-25 | 2010-01-01 |
| 3 | Alexandra | 2017-07-05 | 2017-07-25 | 2010-01-01 |
| 4 | Emilia | 2017-08-05 | 2017-08-25 | 2010-01-01 |
| 5 | Nicoleta | 2017-09-05 | 2017-09-25 | 2010-01-01 |
+----+-----------+------------+------------+-------------+
schedule:
| day | month | name | shifts |
+-----+-------+-----------+--------+
| 1 | 6 | Florin | 0 |
| 1 | 6 | Andrei | 1 |
| 1 | 6 | Alexandra | 2 |
| 1 | 6 | Emilia | 3 |
| 1 | 6 | Nicoleta | 4 |
+-----+-------+-----------+--------+
I need to interrogate table "workers" to give me 2 random names, with minimum shifts number, and workers should not be in vacation period. Also work history must be greater than 18 MONTHS.
In this case, the query i need should return Florin and Andrei.
This is what I've got so far, but it doesn't work as supposed:
SELECT name
FROM workers
WHERE (CURDATE() NOT BETWEEN vacationA AND vacationB) AND
workhistory > (DATE_SUB(CURDATE(), INTERVAL 18 MONTH)) AND
name IN (SELECT name FROM schedule ORDER BY shifts LIMIT 2)
ORDER BY RAND() LIMIT 2;
This query returns
1235 - This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'.
Thank you!

Answer 1

Join to schedule instead and then use LIMIT 2:
SELECT w.name
FROM workers w
INNER JOIN schedule s
ON w.name = s.name
WHERE CURDATE() NOT BETWEEN w.vacationA AND w.vacationB AND
w.workhistory > DATE_SUB(CURDATE(), INTERVAL 18 MONTH)
ORDER BY s.shifts
LIMIT 2;
I don't understand the random ordering, because you are only returning two worker records, and those records are not chosen randomly, but rather belong to the smallest shift numbers.