The invention relates to a sanitary single-handle mixing valve having control elements composed of at least two discs, one of which serves as a fixed valve seat disc with two inlet openings for cold and hot water. For purposes of operating the mixing valve in combination with thermally or hydraulically controlled flow heaters, the centroids of the port areas of the inlet openings, or at least the centroid of the port area of the cold water inlet opening, is shifted a few degrees of angle towards the cold water setting in order to achieve hydraulic asymmetry when the operating handle is in its central position.