Recently I wrote a post on how to split a delimited string in SQL. Now I need to do the reverse and take the flat table and create a delimited string in SQL.

Fortunately creating a delimited string in SQL is far simpler than splitting a delimited string.

Assuming we have a flat table called CountryUsers with the following structure:

Country User
UK Bob
UK Fred
UK Bill
USA Mike
USA Lou
USA Carol
USA Sam

To convert this table into a 2 record table, one for each country, with a comma delimited string of users, run the following SQL:

SELECT DISTINCT a.Country

,STUFF(

(SELECT ‘,’ + b.[User]

FROM CountryUsers b

WHERE b.Country = a.Country

FOR XML PATH ())

,1,1,) as UsersPerCountry

FROM CountryUsers a

 

The output from that SQL are 2 comma separated strings:

Country UsersPerCountry
UK Bob,Fred,Bill
USA Mike,Lou,Carol,Sam

To delimit the string by an alternative delimited, such as a pipe delimiter or semi colon delimiter, change the comma next to the SELECT in the STUFF function to the alternative delimiter, for example SELECT ‘|’ +…