Less than or equal to operator (<=)-PolarDB(PolarDB)-阿里云帮助中心

Compares two raster objects by their universally unique identifiers (UUIDs) and returns true if the UUID of the first object is less than or equal to the UUID of the second.

Syntax

bool Operator <=(raster rast1, raster rast2)

Parameters

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

Note This operator compares UUIDs only — not spatial extents or pixel types. Use it only for operations such as UNION and B-tree index support.

Example

The following query joins two raster tables on matching row IDs and returns a boolean indicating which rows in tbl_a have a UUID less than or equal to the corresponding row in tbl_b. This pattern is useful when building composite queries that require B-tree ordering on raster columns.

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

What's next

Less than operator (<)
Greater than or equal to operator (>=)
Equal operator (=)