The Lord learned all the Vedas with their different branches simply by hearing them once from His teacher, Sāndīpani Muni, whom He rewarded by bringing back his dead son from the region of Yamaloka.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
सान्दीपनेः सकृत्प्रोक्तं ब्रह्माधीत्य सविस्तरम् । तस्मै प्रादाद्वरं पुत्रं मृतं पञ्चजनोदरात्
sāndīpaneḥ sakṛtproktaṃ brahmādhītya savistaram | tasmai prādādvaraṃ putraṃ mṛtaṃ pañcajanodarāt
SB 3.3.2