RegEx pattern any two letters followed by six numbers

Question

Please assist with the proper RegEx matching. Any 2 letters followed by any combination of 6 whole numbers.

These would be valid: 
RJ123456
PY654321
DD321234

These would not
DDD12345
12DDD123

Answer 1

[a-zA-Z]{2}d{6}

[a-zA-Z]{2} means two letters d{6} means 6 digits

If you want only uppercase letters, then:

[A-Z]{2}d{6}