Selecting substring x.x.x.x from a string field - sql

Question

Using Sql Server, I have the following data in a column in a table:
NFPA 1: 4.5.8.1, SFM 69A-21
NFPA 101:7.2.1.8.
NFPA 1 14.13.1.1*
NFPA 101 7.2.1.15.8
NFPA 1 13.6.9.3.1.1.1
NFPA 101:7.1.3.2.1 (6)
?NFPA ?1 14?.?6?.?3?*
I would like to select just records with x.x.x.x.(.x)(.x)etc that have a period sequence. I would also like to show the x.x.x.x.(.x)(.x)etc data in the output and not the data before or after the periods. For example from the above data, the following would display as the output of the sql select:
4.5.8.1
7.2.1.8
14.13.1.1
7.2.1.15.8
13.6.9.3.1.1.1
7.1.3.2.1
[THIS RECORD WOULD NOT BE SELECTED BECAUSE THE DATA IS NOT IN THE FORMAT: ?NFPA ?1 14?.?6?.?3?*]
Any help would be appreciated thanks before hand.
UPDATE: Please check the sql fiddle:
SQL FIDDLE HERE
**UPDATE #2 **: No answers so far, hope someone can help.

Answer 1

Considering that you want a variable number of elements that are a variable number of digits, the best way that I am aware of is to use Regular Expressions. Regular Expressions are not natively available in T-SQL so you need to add SQLCLR functions to so that part. After that, it is just a simple Regular Expression to grab data matching that pattern.
DECLARE #TestData TABLE (String NVARCHAR(100));
INSERT INTO #TestData (String) VALUES ('NFPA 1: 4.5.8.1, SFM 69A-21');
INSERT INTO #TestData (String) VALUES ('NFPA 101:7.2.1.8.');
INSERT INTO #TestData (String) VALUES ('NFPA 1 14.13.1.1*');
INSERT INTO #TestData (String) VALUES ('NFPA 101 7.2.1.15.8');
INSERT INTO #TestData (String) VALUES ('NFPA 1 13.6.9.3.1.1.1');
INSERT INTO #TestData (String) VALUES ('NFPA 101:7.1.3.2.1 (6)');
INSERT INTO #TestData (String) VALUES ('?NFPA ?1 14?.?6?.?3?*');
;WITH cte AS
(
SELECT SQL#.RegEx_MatchSimple(tmp.String, N'\d+(?:\.\d+)+', 1, NULL)
AS [Filtered]
FROM #TestData tmp
)
SELECT *
FROM cte
WHERE cte.Filtered <> '';
Output:
4.5.8.1
7.2.1.8
14.13.1.1
7.2.1.15.8
13.6.9.3.1.1.1
7.1.3.2.1
For the example I used the SQL# library (which I am the author of). The RegEx function used here, and others, are available in the Free version.