plsql query return result into single row as concat

select col1 from tab开发者_StackOverflowlename

returns 2 rows, I want to concat these two data rows into a single column separated by a comma.

You can write a cursor to loop through the returned rows one by one and concatenate as you like.

Here are some examples of same kind of situation: http://www.dba-oracle.com/t_converting_rows_columns.htm