如何使用列的值作为空间操作的输入

Question

给定下面发布的代码或查询，我想使用XOfLowerLeftOfGridCellIntersectingWithBuffersndYOfLowerLeftOfGridCellIntersectingWithBuffer的值作为以下语句的输入：

ST_MakePoint(`XOfLowerLeftOfGridCellIntersectingWithBuffer`,`YOfLowerLeftOfGridCellIntersectingWithBuffer`)

请让我知道我如何才能做到这一点

代码：

 SELECT 
        ST_X((ST_DumpPoints(ST_AsText(ST_Intersection(
            ST_SetSRID(
                ST_MakeEnvelope(
                ST_X(point),
                ST_Y(point),
                ST_X(point)+{width}, 
                ST_Y(point)+{height}),
                25832),ST_Buffer(j.geometry, {bufferRadius}) 
            )))).geom) AS XOfLowerLeftOfGridCellIntersectingWithBuffer,
            ST_Y((ST_DumpPoints(ST_AsText(ST_Intersection(
            ST_SetSRID(
                ST_MakeEnvelope(
                ST_X(point),
                ST_Y(point),
                ST_X(point)+{width}, 
                ST_Y(point)+{height}),
                25832),ST_Buffer(j.geometry, {bufferRadius}) 
            )))).geom) AS YOfLowerLeftOfGridCellIntersectingWithBuffer,

更新：

这是为了进一步澄清我的观点，使之更清楚。我有一个主SELECT语句，如代码1所示。我想将下面发布的with-clasue部分中所示的子句添加到主SELECT的末尾 固定

当我只是复制with clasue并粘贴它时，我在with ITS self子句上收到一个错误。请让我知道如何修理它

代码_1：

SELECT
....
....
....
ST_X((ST_DumpPoints(ST_AsText(ST_Intersection(
            ST_SetSRID(
                ST_MakeEnvelope(
                ST_X(point),
                ST_Y(point),
                ST_X(point)+{width}, 
                ST_Y(point)+{height}),
                25832),ST_Buffer(j.geometry, {bufferRadius}) 
            )))).geom) AS XOfLowerLeftOfGridCellIntersectingWithBufferedZone,
ST_Y((ST_DumpPoints(ST_AsText(ST_Intersection(
    ST_SetSRID(
        ST_MakeEnvelope(
        ST_X(point),
        ST_Y(point),
        ST_X(point)+{width}, 
        ST_Y(point)+{height}),
        25832),ST_Buffer(j.geometry, {bufferRadius})
    )))).geom) AS YOfLowerLeftOfGridCellIntersectingWithBuffer,
    
    
    ST_SetSRID(ST_MakePoint((ST_X((ST_DumpPoints(ST_AsText(ST_Intersection(
            ST_SetSRID(
                ST_MakeEnvelope(
                ST_X(point),
                ST_Y(point),
                ST_X(point)+{width}, 
                ST_Y(point)+{height}),
                25832),ST_Buffer(j.geometry, {bufferRadius}) 
            )))).geom))+5, (ST_Y((ST_DumpPoints(ST_AsText(ST_Intersection(
            ST_SetSRID(
                ST_MakeEnvelope(
                ST_X(point),
                ST_Y(point),
                ST_X(point)+{width}, 
                ST_Y(point)+{height}),
                25832),ST_Buffer(j.geometry, {bufferRadius})
            )))).geom))+5 ),25832) As midPoint,
            
            --WITH clause is to be added here.

与克劳斯一起

WITH j AS (
        SELECT 1 AS X, 2 AS y -- your big query goes here
        ST_X((ST_DumpPoints(ST_AsText(ST_Intersection(
            ST_SetSRID(
                ST_MakeEnvelope(
                ST_X(point),
                ST_Y(point),
                ST_X(point)+{width}, 
                ST_Y(point)+{height}),
                25832),ST_Buffer(j.geometry, {bufferRadius}) 
            )))).geom) AS XOfLowerLeftOfGridCellIntersectingWithBufferedZone,
            T_Y((ST_DumpPoints(ST_AsText(ST_Intersection(
            ST_SetSRID(
                ST_MakeEnvelope(
                ST_X(point),
                ST_Y(point),
                ST_X(point)+{width}, 
                ST_Y(point)+{height}),
                25832),ST_Buffer(j.geometry, {bufferRadius})
            )))).geom) AS YOfLowerLeftOfGridCellIntersectingWithBuffer
            ),
            SELECT ST_MakePoint(XOfLowerLeftOfGridCellIntersectingWithBuffer,YOfLowerLeftOfGridCellIntersectingWithBuffer) As XYPointOfLowerLeftGridCellIntersectingWithBufferedZoneInEPSG25832

小提琴：

https://dbfiddle.uk/?rdbms=postgres_12&fiddle=f2928841af169e69c72faf282f04390b

Answer 1

如果它们必须位于单个查询中，则只需在ST_MakePoint函数中使用ST_X和ST_Y的输出值即可。如果x和y值在列中或是操作的结果，则只需在函数中传递这些值：

SELECT ST_MakePoint(column_x,column_y) FROM t;

或者如果它们在几何体内部

SELECT ST_MakePoint(ST_X(a_geom),ST_Y(a_geom)) FROM t;

使用CTE或子查询（请参见注释）。原理类似，但使用CTE可以创建一个临时集合，并将其用作表。下面的示例生成x和y值并将其命名为j，然后在外部查询中捕获这些值以使用另一个SELECT创建点，但这次使用j：

WITH j AS (
  SELECT 1 AS X, 2 AS y   your big query goes here
) 
SELECT ST_MakePoint(X,Y) FROM j;

将其应用于您的查询

演示（子查询）：^{}

演示（CTE）：^{}

WITH j AS (
 SELECT 
    ST_X((ST_DumpPoints(ST_AsText(ST_Intersection(
        ST_SetSRID(
            ST_MakeEnvelope(
            ST_X(point),
            ST_Y(point),
            ST_X(point)+{width}, 
            ST_Y(point)+{height}),
            25832),ST_Buffer(j.geometry, {bufferRadius}) 
        )))).geom) AS XOfLowerLeftOfGridCellIntersectingWithBuffer,
        ST_Y((ST_DumpPoints(ST_AsText(ST_Intersection(
        ST_SetSRID(
            ST_MakeEnvelope(
            ST_X(point),
            ST_Y(point),
            ST_X(point)+{width}, 
            ST_Y(point)+{height}),
            25832),ST_Buffer(j.geometry, {bufferRadius}) 
        )))).geom) AS YOfLowerLeftOfGridCellIntersectingWithBuffer, 
    ....
)
SELECT ST_MakePoint(XOfLowerLeftOfGridCellIntersectingWithBuffer,
                    YOfLowerLeftOfGridCellIntersectingWithBuffer)
FROM j                  

关于您的问题的一些想法（无法看到全局）：

• ST_AsText在你的查询中毫无意义。你可以摆脱它
• 请注意，用于提取x和y坐标的代码是相同的，ST_DumpPoints已经返回点。所以，我相信你的逻辑是有缺陷的，因为你正在重新创建你之前分割成不同值的相同点