Also G Major (Ionian), A Dorian
D Mixolydian: D E F# G A B C. Formula 1 2 3 4 5 6 ♭7. Same notes as G Major (Ionian), A Dorian, B Phrygian. A major mode with a flat 7th: the sound of the dominant chord, of blues-rock riffs and of much folk and Celtic music.