How to get N set of data base on one column
MySQL 8+

WITH cte AS ( SELECT *, 
                     DENSE_RANK() OVER (ORDER BY order_time) dr
              FROM my_table
              WHERE &lt;conditions&gt; )
SELECT xxx,
       yyy,
       order_time
FROM cte
WHERE dr &lt;= 3


MySQL 5.+

SELECT my_table.*
FROM my_table 
JOIN ( SELECT DISTINCT order_time 
       FROM my_table 
       WHERE &lt;conditions&gt;
       ORDER BY order_time 
       LIMIT 3 ) times USING (order_time)
/* WHERE &lt;conditions&gt; */