I have a table that unfortunately, I can't alter in any way and have to work with what I have.
The mysql table has a field labeled, "customer_id". It has 2 prefixed letters with a 4-value numerical number.
How can I select the largest numerical value with a certain prefix? For example, assume that I wanted to select the largest number with a prefix of HE. How can I select that value?
Any help is absolutely appreciated. I've been stuck for a while now.
Since all values left padded you can do
SELECT RIGHT(MAX(customer_id), 4) max_val FROM table1 WHERE customer_id LIKE 'HE%'
Make sure that you have an index on
customer_id which you probably do based on a name of the column.
LIKE will most likely use it.
Here is SQLFiddle demo