SELECT objectId, taiMidPoint, fluxToAbMag(psfMag) FROM Source JOIN Object USING(objectId) JOIN Filter USING(filterId) WHERE areaSpec_box(:raMin, :declMin, :raMax, :declMax) AND filterName = 'u' AND variability BETWEEN :varMin AND :varMax ORDER BY objectId, taiMidPoint ASC
Note: we don't have ''variability'' in the schema yet, but it would be in Object, not Source.