comparing a date value in one table against multiple values in another to categorise by age

I have created a form which allows users to enter multiple, unlimited month number values and label them to use against inventory to categorise the age of each item. **Table 1 - AgeConfig - Manually enterted by users** id | customer_id | start_month | label ---|-------------|-------------|---------- 1 | 171 | 0 | Current 2 | 171 | 3 | 3-6 Months 3 | 171 | 6 | 6-12 Months 4 | 171 | 12 | 12+ Months **Table 2 - Inventory** id | customer_id | item_no | entry_date | qty | cost ----|-------------|---------|------------|-----|-------- 1 | 171 | CH72394 | 2022-01-28 | 3 | 430.10 1 | 171 | CH72395 | 2022-02-28 | 4 | 30.10 1 | 171 | CH72396 | 2022-03-28 | 1 | 130.10 1 | 171 | CH72397 | 2022-01-22 | 5 | 320.50 1 | 171 | CH72398 | 2022-02-22 | 1 | 22.30 1 | 171 | CH72399 | 2022-01-22 | 1 | 92.30 1 | 171 | CH72400 | 2022-01-24 | 1 | 392.80 I am trying to present this in SQL using CASE but I dont know how to compare it against a variable number of rows and make sure I start at the highest and work to the lowest. I am trying to use CASE but am stumped

SELECT  customer_id,
	item_no,
	entry_date,
	CASE
	    WHEN (TIMESTAMPDIFF(MONTH, entry_date, NOW()) > MAX(start_month)) THEN label
	    WHEN (TIMESTAMPDIFF(MONTH, entry_date, NOW()) > 2NDMAX(start_month)) THEN label
	    WHEN (TIMESTAMPDIFF(MONTH, entry_date, NOW()) > 3RDMAX(start_month)) THEN label
	    ...
	END,
	qty,
	cost
FROM Inventory
INNER JOIN AgeConfig USING (customer_id)
WHERE customer_id = 171

I dont know how to incrementally test against highest down to lowest and then use the corresponding label so that the result is: id | customer_id | item_no | entry_date | age | qty | cost ----|-------------|---------|------------|-------------|-----|------ 1 | 171 | CH72394 | 2022-01-28 | 3-6 Months | 3 | 430.10 1 | 171 | CH72395 | 2022-02-28 | Current | 4 | 30.10 1 | 171 | CH72396 | 2021-03-28 | Current | 1 | 130.10 1 | 171 | CH72397 | 2022-01-22 | 3-6 Months | 5 | 320.50 1 | 171 | CH72398 | 2021-08-22 | 6-12 Months | 1 | 22.30 1 | 171 | CH72399 | 2021-01-22 | 12+ Months | 4 | 92.30 1 | 171 | CH72400 | 2022-01-24 | 3-6 Months | 1 | 392.80