STDisjoint (geography Data Type)
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Returns 1 if a geography instance is spatially disjoint from another geography instance. Returns 0 if it is not.
Syntax
.STDisjoint ( other_geography )
Arguments
other_geography
Is another geography instance to compare against the instance on which STDisjoint() is invoked.
Return Types
SQL Server return type: bit
CLR return type: SqlBoolean
Remarks
Two geography instances are disjoint if the intersection of their point sets is empty.
This method always returns null if the spatial reference IDs (SRIDs) of the geography instances do not match.
Examples
The following example uses STDisjoint() to test two geography instances to see if they are spatially disjoint.
DECLARE @g geography;
DECLARE @h geography;
SET @g = geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656)', 4326);
SET @h = geography::STGeomFromText('POINT(-122.34900 47.65100)', 4326);
SELECT @g.STDisjoint(@h);