above_stbox_stbox above_stbox_stbox_internal adjacent_stbox_stbox adjacent_stbox_stbox_internal after_stbox_stbox after_stbox_stbox_internal back_stbox_stbox back_stbox_stbox_internal before_stbox_stbox before_stbox_stbox_internal below_stbox_stbox below_stbox_stbox_internal box2d_to_stbox box3d_to_stbox contained_stbox_stbox contained_stbox_stbox_internal contains_stbox_stbox contains_stbox_stbox_internal DatumGetSTboxP ensure_has_T_stbox ensure_has_X_stbox front_stbox_stbox front_stbox_stbox_internal geo_period_to_stbox geo_timestamp_to_stbox geo_to_stbox geo_to_stbox_internal geodstbox_constructor geodstbox_constructor_t geodstbox_constructor_z geodstbox_constructor_zt left_stbox_stbox left_stbox_stbox_internal overabove_stbox_stbox overabove_stbox_stbox_internal overafter_stbox_stbox overafter_stbox_stbox_internal overback_stbox_stbox overback_stbox_stbox_internal overbefore_stbox_stbox overbefore_stbox_stbox_internal overbelow_stbox_stbox overbelow_stbox_stbox_internal overfront_stbox_stbox overfront_stbox_stbox_internal overlaps_stbox_stbox overlaps_stbox_stbox_internal overleft_stbox_stbox overleft_stbox_stbox_internal overright_stbox_stbox overright_stbox_stbox_internal period_to_stbox period_to_stbox_internal periodset_to_stbox periodset_to_stbox_internal PG_GETARG_STBOX_P PG_RETURN_STBOX_P right_stbox_stbox right_stbox_stbox_internal same_stbox_stbox same_stbox_stbox_internal stbox_cmp stbox_cmp_internal stbox_constructor stbox_constructor_t stbox_constructor_z stbox_constructor_zt stbox_copy stbox_eq stbox_eq_internal stbox_expand stbox_expand_spatial stbox_expand_spatial_internal stbox_expand_temporal stbox_expand_temporal_internal stbox_ge stbox_geodetic stbox_gt stbox_hast stbox_hasx stbox_hasz stbox_in stbox_intersection stbox_intersection_internal stbox_le stbox_lt stbox_make stbox_ne stbox_out stbox_set stbox_set_precision stbox_set_srid stbox_shift_tscale stbox_srid stbox_tmax stbox_tmin stbox_to_box2d stbox_to_box3d stbox_to_box3d_internal stbox_to_gbox stbox_to_period stbox_transform stbox_union stbox_union_internal stbox_xmax stbox_xmin stbox_ymax stbox_ymin stbox_zmax stbox_zmin STboxPGetDatum timestamp_to_stbox timestamp_to_stbox_internal timestampset_to_stbox timestampset_to_stbox_internal

stbox_zmin() Datum stbox_zmin ( PG_FUNCTION_ARGS  ) Returns the minimum Z value of the spatiotemporal box.