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

As an exercise in futility (your current solition would probably be faster and prefered), if the table is MYISAM (or you can live with the approximation of InnoDB):

SET @row =0;
SELECT x.*
FROM information_schema.tables
JOIN (
  SELECT @row := @row+1 as 'row',mydata.*
  FROM mydata
  ORDER BY field ASC
) x
ON x.row = round(information_schema.tables.table_rows * 0.4)
WHERE information_schema.tables.table_schema = database()
AND information_schema.tables.table_name = 'mydata';