Albert Barnes Commentary 2 Samuel 23:9

"And after him was Eleazar the son of Dodai the son of an Ahohite, one of the three mighty men with David, when they defied the Philistines that were there gathered together to battle, and the men of Israel were gone away." — 2 Samuel 23:9 (ASV)

Gone away - Rather, this means they went up to battle (2 Samuel 5:19; 2 Kings 3:21, etc.) against them. These words, and what follows as far as the word “troop” (2 Samuel 23:11), have been omitted from the text in Chronicles. The effect of this omission is that it leaves out Eleazar’s feat as described here, attributes Shammah’s victory to him, incorrectly places the flight of the Israelites, and removes Shammah altogether from the list of David’s mighty men.