有没有一个聚合函数的功能类似于stuion()?

SQL Server提供了一些 aggregate methods on geometries ,包括UnionAggregate和CollectionAggregate,它们在两种以上的形状上运行。

从 UnionAggregate 例子:

-- Setup table variable for UnionAggregate example 
DECLARE @Geom TABLE 
( 
shape geometry, 
shapeType nvarchar(50) 
);
 
INSERT INTO @Geom(shape,shapeType) 
VALUES
('CURVEPOLYGON(CIRCULARSTRING(2 3, 4 1, 6 3, 4 5, 2 3))', 'Circle'), 
('POLYGON((1 1, 4 1, 4 5, 1 5, 1 1))', 'Rectangle'); 

-- Perform UnionAggregate on @Geom.shape column 
SELECT geometry::UnionAggregate(shape).ToString() 
FROM @Geom;

这就产生了

CURVEPOLYGON (COMPOUNDCURVE (
  (1 1, 4 1, 4.0000000000000071 1.0000000000000218), 
  CIRCULARSTRING (4.0000000000000071 1.0000000000000218, 
    5.4142135623730905 1.5857864376269268,
    6 3, 
    5.4142135623730905 4.4142135623730905, 
    4.0000000000000071 4.9999999999999947), 
  (4.0000000000000071 4.9999999999999947, 1 5, 1 1))
)