SQLServerのgeography型をポリゴンで検索する場合は左回りである必要があります

SELECT 
    * 
FROM 
    customers 
WHERE 
    location.STIntersects(geography::STGeomFromText('POLYGON((139.781225 35.686380, 139.782368 35.683731, 139.777267 35.683319, 139.781225 35.686380))', 4326)) = 1

SELECT 
    *
FROM 
    customers 
WHERE 
    location.STIntersects(geography::STGeomFromText('POLYGON((139.781225 35.686380, 139.777267 35.683319, 139.782368 35.683731, 139.781225 35.686380))', 4326)) = 1

// 右回りの座標 
var coordinates = new[] { 
        new Coordinate(139.781225, 35.686380), 
        new Coordinate(139.777267, 35.683319), 
        new Coordinate(139.782368, 235.683731), 
        new Coordinate(139.781225, 35.686380) 
}; 
var polygon = new Polygon(new LinearRing(coordinates)); 
if(!polygon.Shell.IsCCW){ 
    // 右回りなら座標を逆転させる 
    coordinates = coordinates.Reverse().ToArray(); 
}