On which day has it neither been foggy nor rained in the zip code of 94107?
SELECT date FROM weather WHERE zip_code  =  94107 AND EVENTS != "Fog" AND EVENTS != "Rain"
neither been foggy nor rained refers to EVENTS != 'Fog' AND EVENTS != 'Rain'; on which day refers to date; in the zip code of 94107 refers to zip_code = 94107;