Select nth percentile from MySQL

Question

I have a simple table of data, and I\'d like to select the row that\'s at about the 40th percentile from the query.

I can do this right now by first querying to find

Answer 1

There's also this solution, which uses a monster string made by GROUP_CONCAT. I had to up the max on the output like so to get it to work:

SET SESSION group_concat_max_len = 1000000;

MySql wizards out there: feel free to comment on the relative performance of the methods.