Asahel (verse 7), who is mentioned in 1 Chr 11.26, was killed before David became king of the whole country (see 2 Sam 2.18-23), and his son took his place.
Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on 1-2 Chronicles, Volume 1. (UBS Helps for Translators). Miami: UBS, 2014. For this and other handbooks for translators see here .