How to trim text from SQL Server select statement for text consisting of two letters and five digits?

Question

I would like to write a select query to output only the text containing of two letters and five digits.

The data type is varchar(max).

Each column may contain more than one of these numbers and also may contain a lots of other text. The server is a SQL Server 2012.

Sample data 1:

Reg.nr: AA11111, Dette er et teksttekst pa et test abonnement.
Referanse: Faktura 2222222222, Beløp: 1572.91,
Referanse: Purregebyr, Beløp: -64.00.

12.12.12 13:00:00 AAA
Utring ingen svar

18.12.14 18:00:00 BBB
tekst tekst tekst

14.01.15 15:00:00 CCC
tekst tekst tekst

Sample data 2:

text text text
AA11111 text,
BB22222 text,
text text

Desired output:

Sample data 1: AA11111
Sample data 2: AA11111, BB22222

Answer 1

Try this:

SELECT 
    SUBSTRING(col, PATINDEX('%[a-zA-Z][a-zA-Z][0-9][0-9][0-9][0-9][0-9]%', '' + col), 7)
FROM TEST
WHERE PATINDEX('%[a-zA-Z][a-zA-Z][0-9][0-9][0-9][0-9][0-9]%', '' + col) <> 0

Here is a SQLFiddle with how the query works.