Question

I want to be able to differentiate between a string that is alphnumeric and a string that is in hex format.

My current query is:

<columnName> LIKE '?_____=' + REPLICATE('[0-9A-Fa-f]',16)

I found this method of searching for hex ID’s online and I thought it was working. However after getting a significantly larger sample size I can see a high false positive rate in my results. The problem is that this gives me all the results I do want but it also gives me a bunch of results I dont care about. For example:

I want to see:

<url>.php?mains=d7ad916d1c0396ff

but i dont want to see:

<url>.php?mblID=2007012422060265

The difference between the 2 strings is that the 16 characters at the end that i want to collect are all numeric and not a hex ID. What are some ways you guys use to limit the results to hex ID only? Thanks in advnace.

UPDATE:
Juergen brought up a good point, the second number could be a hex value to. Not all hex numbers contain [a-F]. I would like to rephrase the question to state that I am looking for an ID with both letters and numbers in it, not just numbers.

Answer 1

The simplest way is just to add a separate clause for that restriction:

    <columnName> LIKE '?_____=' + REPLICATE('[0-9A-Fa-f]',16)
AND <columnName> NOT LIKE '?_____=' + REPLICATE('[0-9]',16)