Comma separated list of values of single Database table field

Many times you need to create a comma seperated list of values in a table. Here is a line of T-SQL solution to get comma separated list of values of single field of a database table.

DECLARE @commaSeparatedVal AS VARCHAR(MAX);
SELECT @commaSeparatedVal = ISNULL(@commaSeparatedVal +',','') + CONVERT(VARCHAR,[SKU]) 
FROM PRODUCT;
PRINT @commaSeparatedVal;