Greater than operator (>)-PolarDB(PolarDB)-阿里云帮助中心

The > operator compares two raster objects by their universally unique identifiers (UUIDs) and returns true if the UUID of the first object is greater than the UUID of the second.

Note This operator compares UUIDs only — not spatial extents or pixel types. It is used only for operations such as union and B-tree. Do not use it to compare the spatial content of raster objects.

Syntax

bool Operator >(raster rast1, raster rast2);

Parameters

Parameter	Description
`rast1`	The first raster object.
`rast2`	The second raster object.

Example

The following query compares matched raster objects from two tables by UUID:

SELECT a.rast > b.rast
FROM tbl_a a, tbl_b b
WHERE a.id = b.id;

The query returns a Boolean value for each matched row: true if the UUID of a.rast is greater than the UUID of b.rast, or false otherwise.