How to compare Date in SQlite?

How to compare dates which stored as String in Sqlite Database and fetch data...?

I am storing date in a format DD.MM.YY

I have tried <= but it is working. And I want to compare only Date and not Time. So I am passing value as dd.mm.yy

I have tried "Select SUM(tramount) as s From mytrans where accno = " + acno + " AND trdate <= Datetime( '"+date+"' )" this too,but it is not working.