You can concatenate strings separated by delimiter using the string_agg() function.
If your individuals table is:
Name | Age| Country | –– | —| –– | Allie | 15 | USA | Amanda | 14 | USA | Alana | 20 | Russia |
You could write SELECT ... GROUP BY statement to get names from each country:
SELECT string_agg(name, ', ') AS names, country
FROM individuals
GROUP BY country;
Note that you need to use a GROUP BY clause because string_agg() is an aggregate function.
Result:
names | country | —– | —–– | Allie, Amanda | USA | Alana | Russia |