MySQL: Complex Sorting Based on Item and Max Value

Data and Databases
1

I’m struggling with a tricky sorting problem in MySQL. Here’s what I need:

  1. Sort items by their highest value
  2. For each item, list all its values in descending order
  3. Move to the next item with the highest value and repeat

For instance, if I have this data:

Item | Value
X    | 5
X    | 3
Y    | 7
Y    | 2
Z    | 4
Z    | 1

I want it sorted like this:

Item | Value
Y    | 7
Y    | 2
X    | 5
X    | 3
Z    | 4
Z    | 1

How can I achieve this in MySQL? Regular ORDER BY doesn’t seem to cut it. Any ideas?

2

This sorting challenge can be tackled using a combination of subqueries and window functions. Here’s an approach that should work:

  1. Use a subquery to get the maximum value for each item.
  2. Join this result back to the original table.
  3. Employ window functions to create a sorting key.

The query might look something like this:

SELECT t.Item, t.Value
FROM (
    SELECT Item, Value,
           ROW_NUMBER() OVER (PARTITION BY Item ORDER BY Value DESC) as rn,
           RANK() OVER (ORDER BY MAX(Value) OVER (PARTITION BY Item) DESC) as rnk
    FROM YourTable
) t
ORDER BY rnk, Item, rn;

This solution first ranks items by their maximum value, then sorts within each item. It’s efficient and scalable for larger datasets.

3

yo, try window functions. using RANK() and ROW_NUMBER() can order items by max value then sort each. i reckon a query like SELECT col, RANK() OVER(ORDER BY max_val DESC), ROW_NUMBER() OVER(PARTITION BY item ORDER BY val DESC) FROM table; could do it. why not gve it a shot?

4

ooh, interesting problem! have u tried using a subquery to get the max value for each item? then u could join that back to ur original table and sort by the max value first, then the actual value. might work? what other approaches have u considered so far?