从SQL的表列中提取2个字母的大写子字符串

Question

I have an SQL table on users where particular accounts are tagged with country code (2 letter words in uppercase) while other substrings in the tags (all separated by commas) are either in lowercase or more than 2 letters long.

In user table Eg:

id               User_tags
1                alu,US,ATD
2                GB,xx
3                ol,tuds,FR

Users 1,2 and 3 are tagged to countries US, GB and FR and I need to extract them from the user_tags column. I understand that regex functions are needed but I am not able to make them work in an SQL query.

Answer 1

Create a country code ref table and join to using the below. I don't have sqlserver open, so unable to double check syntax , but it should work.

Select * 
From yourtable y left join refcountry r
On charindex (r.code+’,’,y.string+’,’)>0

Note this might be slow for a large dataset

If not sqlserver find the equiv function for charindex in your rdbms