Getting comments from RT database

i created a ticket in the RT and added some comments to it. The comments can be seen in the UI side. Now i need to fetch this comment from the RT database . For that first I query the transaction table by giving the Type = “comment” and object id. from the results I took the transaction id of the ticket and query the attachment table using this transaction id. But still I did not get the column with comments. Can someone please help me to find the comments column?