How to turn one column of a table into a csv string in SQL Server without using a cursor

Question

I want to return the results of select Column from Table into a comma separated string using SQL Server.

The column in question is rather large (n

Answer 1

STRING_AGG was added in sql 2017

https://docs.microsoft.com/en-us/sql/t-sql/functions/string-agg-transact-sql?view=sql-server-2017

SELECT STRING_AGG (ColumnName, ',') AS csv 
FROM TableName
GROUP BY ColumnName2