Jamieson, Fausset and Brown on 2 Samuel 23:8

8. These be the names of the mighty men whom David had--This verse should be translated thus: He who sits in the seat of the Tachmonite (that is, of Jashobeam the Hachmonite), who was chief among the captains, the same is Adino the Eznite; he lift up his spear against eight hundred, whom he slew at one time. The text is corrupt in this passage; the number eight hundred should be three hundred [Davidson, Hermeneutics]. Under Joab he was chief or president of the council of war. The first or highest order was composed of him and his two colleagues, Eleazar and Shammah. Eleazar seems to have been left to fight the Philistines alone; and on his achieving the victory, they returned to the spoil. In like manner Shammah was left to stand alone in his glory, when the Lord, by him, wrought a great victory. It is not very easy to determine whether the exploits that are afterwards described were performed by the first or the second three.