插入緩衝的GEOGRAPHY將點放入目標表中，不需要重複

Question

我想從源表創建一個目標表，它只包含唯一/不同的點，因爲在彼此相距1000米半徑範圍內應該沒有點。

這是（使用簡化的實體模型臨時表）的起點：

IF OBJECT_ID('tempdb..#Source') IS NOT NULL DROP TABLE #Source 
IF OBJECT_ID('tempdb..#TargetSeeded') IS NOT NULL DROP TABLE #TargetSeeded 
IF OBJECT_ID('tempdb..#TargetEmpty') IS NOT NULL DROP TABLE #TargetEmpty 

CREATE TABLE #Source 
(
    Id INT IDENTITY(1,1) PRIMARY KEY, 
    Point GEOGRAPHY 
) 

CREATE TABLE #TargetSeeded 
(
    Id INT IDENTITY(1,1) PRIMARY KEY, 
    Point GEOGRAPHY 
) 

CREATE TABLE #TargetEmpty 
(
    Id INT IDENTITY(1,1) PRIMARY KEY, 
    Point GEOGRAPHY 
) 

DECLARE @Point1 GEOGRAPHY; 
DECLARE @Point2 GEOGRAPHY; 
DECLARE @Point3 GEOGRAPHY; 
DECLARE @Point4 GEOGRAPHY; 
DECLARE @PointBufferDistanceInMeters INT; 

SET @Point1 = GEOGRAPHY::STPointFromText('POINT(1 52.50)', 4326); 
SET @Point2 = GEOGRAPHY::STPointFromText('POINT(1 52.51)', 4326); 
SET @Point3 = GEOGRAPHY::STPointFromText('POINT(1 52.52)', 4326); 
SET @Point4 = GEOGRAPHY::STPointFromText('POINT(1 52.52)', 4326); 
SET @PointBufferDistanceInMeters = 1000; 

--SELECT @Point1.STDistance(@Point2); 
--SELECT @Point1.STDistance(@Point3); 
--SELECT @Point1.STDistance(@Point4); 
--SELECT @Point2.STDistance(@Point3); 

INSERT INTO #Source 
    SELECT @Point1 
     UNION ALL 
    SELECT @Point2 
     UNION ALL 
    SELECT @Point3 
     UNION ALL 
    SELECT @Point4 

INSERT INTO #TargetSeeded 
    SELECT @Point1 
     UNION ALL 
    SELECT @Point2 

CREATE SPATIAL INDEX SpatialIndex ON #Source([Point]); 
CREATE SPATIAL INDEX SpatialIndex ON #TargetEmpty([Point]); 
CREATE SPATIAL INDEX SpatialIndex ON #TargetSeeded([Point]); 

-- Identify Ids to be inserted 
SELECT 
    Id, 
    Point 
FROM #Source WHERE Id NOT IN 
(
    SELECT 
     So.Id 
    FROM #Source AS So 
    INNER JOIN #TargetSeeded AS Ta 
    ON So.Point.STDistance(Ta.Point) < @PointBufferDistanceInMeters 
) 

我可以識別候選能夠從#Source插入作爲在（IMHO）組爲基礎的方法有效的方式（？）。我只是不知道如何刪除#Source表中的重複項（在上述意義上重複 - 具有1000米的緩衝區）。所以最終，我想將id 3或4插入#TargetSeeded（哪一個不重要）。有任何想法嗎？

PS：

這是一個相關子查詢的企圖可能是一個解決辦法：

IF OBJECT_ID('tempdb..#Source') IS NOT NULL DROP TABLE #Source 
IF OBJECT_ID('tempdb..#TargetSeeded') IS NOT NULL DROP TABLE #TargetSeeded 
IF OBJECT_ID('tempdb..#TargetEmpty') IS NOT NULL DROP TABLE #TargetEmpty 

CREATE TABLE #Source 
(
    Id INT IDENTITY(1,1) PRIMARY KEY, 
    Point GEOGRAPHY 
) 

CREATE TABLE #TargetSeeded 
(
    Id INT IDENTITY(1,1) PRIMARY KEY, 
    Point GEOGRAPHY 
) 

CREATE TABLE #TargetEmpty 
(
    Id INT IDENTITY(1,1) PRIMARY KEY, 
    Point GEOGRAPHY 
) 

DECLARE @Point1 GEOGRAPHY; 
DECLARE @Point2 GEOGRAPHY; 
DECLARE @Point3 GEOGRAPHY; 
DECLARE @Point4 GEOGRAPHY; 
DECLARE @PointBufferDistanceInMeters INT; 

SET @Point1 = GEOGRAPHY::STPointFromText('POINT(1 52.50)', 4326); 
SET @Point2 = GEOGRAPHY::STPointFromText('POINT(1 52.51)', 4326); 
SET @Point3 = GEOGRAPHY::STPointFromText('POINT(1 52.52)', 4326); 
SET @Point4 = GEOGRAPHY::STPointFromText('POINT(1 52.52)', 4326); 
SET @PointBufferDistanceInMeters = 1000; 

--SELECT @Point1.STDistance(@Point2); 
--SELECT @Point1.STDistance(@Point3); 
--SELECT @Point1.STDistance(@Point4); 
--SELECT @Point2.STDistance(@Point3); 

INSERT INTO #Source 
    SELECT @Point1 
     UNION ALL 
    SELECT @Point2 
     UNION ALL 
    SELECT @Point3 
     UNION ALL 
    SELECT @Point4 

INSERT INTO #TargetSeeded 
    SELECT @Point1 
     UNION ALL 
    SELECT @Point2 

CREATE SPATIAL INDEX SpatialIndex ON #Source([Point]); 
CREATE SPATIAL INDEX SpatialIndex ON #TargetEmpty([Point]); 
CREATE SPATIAL INDEX SpatialIndex ON #TargetSeeded([Point]); 

-- Identify Ids to be inserted 
DELETE FROM #Source WHERE Id NOT IN 
(
    SELECT 
     Id 
    FROM #Source WHERE Id NOT IN 
    (
     SELECT 
      So.Id 
     FROM #Source AS So 
     INNER JOIN #TargetSeeded AS Ta 
     ON So.Point.STDistance(Ta.Point) < @PointBufferDistanceInMeters 
    ) 
) 

SELECT 
    * 
FROM #Source o 
WHERE o.Id IN 
(
    SELECT MAX(i.Id) 
    FROM #Source i 
    WHERE 
     i.Point.STDistance(o.Point) < @PointBufferDistanceInMeters 
) 

Answer 1

這是否幫助？

-- Sample data. 
declare @Source as Table (Id Int Identity Primary Key, Point Geography); 
insert into @Source (Point) values 
    (Geography::STPointFromText('Point(1 52.50)', 4326)), 
    (Geography::STPointFromText('Point(1 52.51)', 4326)), 
    (Geography::STPointFromText('Point(1 52.52)', 4326)), 
    (Geography::STPointFromText('Point(1 52.52)', 4326)); 
select *, Point.ToString() as DecodedPoint from @Source; 

declare @Target as Table (Id Int Identity Primary Key, Point Geography); 
insert into @Target (Point) values 
    (Geography::STPointFromText('Point(1 52.50)', 4326)), 
    (Geography::STPointFromText('Point(1 52.51)', 4326)); 
select *, Point.ToString() as DecodedPoint from @Target; 

declare @PointBufferDistanceInMeters as Int = 1000; 

-- Merge the data.  
insert into @Target 
    select Point 
    from @Source as S 
    where 
     -- Remove rows that conflict with another Source row. 
     not exists (select 42 from @Source where S.Point.STDistance(Point) < @PointBufferDistanceInMeters and S.Id < Id) and 
     -- Remove rows that conflict with an existing Target row. 
     not exists (select 42 from @Target where S.Point.STDistance(Point) < @PointBufferDistanceInMeters) 
select *, Point.ToString() as DecodedPoint from @Target;