Means, first character must be a DIGIT and the last 2 must be ALPHABETS.
Next, the other text box must have data like below format.
Thanks Ali !
In your pattern :
the first A-Z0-9 means it can have alphabets and numbers, so if I only want numbers there, can i make it :
Exactly, that would only accept numbers, not letters for the first character. Everytime you use a hyphen, regex includes everything in between the respective Unicode code points; since capital letters, lower-case letters, and numbers each have contiguous spots, you can call each group together.
If you look over the Unicode charts you can include any set of contiguous characters in this way.