ST_SetBandNoDataValue — 设置表示无数据的给定标注栏的值。如果未指定波段，则假定波段1。要将波段标记为没有nodata值，请将nodata值设置为NULL。
raster
ST_SetBandNoDataValue
(
raster
rast
, double precision
nodatavalue
)
;
raster
ST_SetBandNoDataValue
(
raster
rast
, integer
band
, double precision
nodatavalue
, boolean
forcechecking=false
)
;
-- change just first band no data value
UPDATE dummy_rast
SET rast = ST_SetBandNoDataValue(rast,1, 254)
WHERE rid = 2;
-- change no data band value of bands 1,2,3
UPDATE dummy_rast
SET rast =
ST_SetBandNoDataValue(
ST_SetBandNoDataValue(
ST_SetBandNoDataValue(
rast,1, 254)
,2,99),
3,108)
WHERE rid = 2;
-- wipe out the nodata value this will ensure all pixels are considered for all processing functions
UPDATE dummy_rast
SET rast = ST_SetBandNoDataValue(rast,1, NULL)
WHERE rid = 2;