Microsoft SQL Server - Get first n alphanumeric characters with variable length, meeting ABCD-1234 or ABCD-1234567 format

My MS SQL 2019 server version is 15.0.2080.9 (X64) I have a table like | id | message | | -------- | -------------- | | 2003 | ABCD-1234: some text | | 2897 | ABCD-5678 | | 2456 | ABCD-675456: some text | | 3204 | ABCD-4512345 :some text | | 4567 | ABCD-2345 | My requirement is to create another column in SELECT query, for each row to get like | id | message | key | -------- | -------------- | -------------- | | 2003 | ABCD-1234: some text | ABCD-1234 | 2897 | ABCD-5678 | ABCD-5678 | 2456 | ABCD-675456 some text | ABCD-675456 | 3204 | ABCD-4512345 :some text |ABCD-4512345 | 4567 | ABCD-2345 |ABCD-2345 Meaning I need from position 0 till ABCD-1234 format is satisfied discarding empty or any other text after that. I tried LEFT, RIGHT and Substring but could not find a way to get the exact length to meet the regex criteria from position 0. Can you please help me out? Thanks in advance