John Gill Commentary 1 Samuel 14:49

"Now the sons of Saul were Jonathan, and Ishvi, and Malchishua; and the names of his two daughters were these: the name of the first-born Merab, and the name of the younger Michal:" — 1 Samuel 14:49 (ASV)

And the sons of Saul were Jonathan
Who seems to be his firstborn, of whom, his valour and success, we read in this and the preceding chapter:

and Ishui ;
the same with Abinadab, (1 Chronicles 8:33) (9:39) for he had two names:

and Melchishua ;
and besides these three there was another, whose name was Ishbosheth, sometimes called Eshbaal, (2 Samuel 2:8) (1 Chronicles 8:33) who succeeded him in the kingdom; for which reason Abarbinel thinks he is not mentioned here, because he was a king; though it is generally supposed the reason why these only are named is, because they went out to war with him, and died with him, but this did not; he had other children by a concubine, or secondary wife, whose name was Rizpah, not mentioned here, (2 Samuel 21:8) ,

and the names of his two daughters were these, the name of the
firstborn Merab ;
who was afterwards married to Adriel the Meholathite, (1 Samuel 18:19) and the name of the younger Michal; who became the wife of David, (1 Samuel 18:27) .