kesavan@home$adb shell
shell@hammerhead:/ $ su
root@hammerhead:/ # sqlite3 /data/data/com.android.providers.contacts/databases/contacts2.db
SQLite version 3.7.11 2012-03-20 11:35:50
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .mode column
.mode column
sqlite> .headers on
.headers on
sqlite> delete from calls where _id not in( select  min(_id) from calls group by date ) ;
sqlite> SELECT _id,/*number,name*/ date,datetime(date/1000,'unixepoch','localtime') timestamp,duration,countryiso,geocoded_location FROM calls ORDER BY date LIMIT 10  ;
^D

# NOUGAT - com.android.providers.contacts/databases/calllog.db