The melody of Who Knew by P!nk runs 301 notes across 68 bars, 3:24 long in A at 140 beats per minute. The tab sits low on the neck, mostly under the fourth fret, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? Who Knew chords and lyrics.