ST_Percentile for calculating the percentile of a raster band - PolarDB

Queries the pixel value at a specified percentile for a raster band.

Syntax

float8 ST_Percentile(raster raster_obj,
                     integer band,
                     integer percentage)

Parameters

Parameter	Description
`raster_obj`	The raster object.
`band`	The band IDs to query. Example: `'0,1-3,6,8'`. Valid band IDs start from `0`. To query all bands, set this parameter to `''`.
`percentage`	The percentile rank for which to return the pixel value. You can use ST_BuildPercentiles or ST_ComputeStatistics to obtain the percentage.

Examples

The following example returns the pixel value at the 10th percentile for band 0:

SELECT st_percentile(rast_obj, 0, 10)
FROM raster_table
WHERE id = 1;

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ST_Percentile can also implement the behavior of ST_Quantile. The following example returns pixel values at the 25th and 50th percentiles for band 0:

SELECT st_percentile(rast_obj, 0, 25), st_percentile(rast_obj, 0, 50)
FROM raster_table
WHERE id = 1;