&& — Returns TRUE if A's bounding box intersects B's bounding box.
boolean &&(
                        raster 
                        A
                    , 
                        raster 
                        B
                    );
boolean &&(
                        raster 
                        A
                    , 
                        geometry 
                        B
                    );
boolean &&(
                        geometry 
                        B
                    , 
                        raster 
                        A
                    );
The && operator returns TRUE if the bounding box of raster/geometr A intersects the bounding box of raster/geometr B.
                 
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                 This operand will make use of any indexes that may be available on the rasters.  | 
            
Availability: 2.0.0
SELECT A.rid As a_rid, B.rid As b_rid, A.rast && B.rast As intersect
 FROM dummy_rast AS A CROSS JOIN dummy_rast AS B LIMIT 3;
 a_rid | b_rid | intersect
-------+-------+---------
     2 |     2 | t
     2 |     3 | f
     2 |     1 | f