如何使用列的值作为空间操作的输入

Question

给出下面发布的代码或查询，我想使用 XOfLowerLeftOfGridCellIntersectingWithBuffer 和 YOfLowerLeftOfGridCellIntersectingWithBuffer 的值作为以下语句的输入：

ST_MakePoint(`XOfLowerLeftOfGridCellIntersectingWithBuffer`,`YOfLowerLeftOfGridCellIntersectingWithBuffer`)

请让我知道我怎样才能做到这一点

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:

这是为了进一步阐明我的观点并使之更清楚。我有一个主要的 SELECT 语句，如代码 1 所示。我想添加 WITH 子句，即下面发布的 with-clasue 部分中显示的子句到主要 SELECT 的末尾声明

当我只是复制并粘贴 with 子句时，我收到了 with 子句本身的错误。请告诉我如何解决它

code_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.

和克劳斯

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

fiddle:

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

Answer 1

如果它们必须在单个查询中，您只需在 ST_MakePoint 函数中使用 ST_X 和 ST_Y 的输出值。如果 x 和 y 值在列中或者是操作的结果，您只需在函数中传递这些值：

SELECT ST_MakePoint(column_x,column_y) FROM t;

或者万一它们在几何内部..

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

使用 CTE 或子查询（见评论）。原理是相似的，但是使用 CTE 可以创建一个临时集并将其用作 table。以下示例生成 x 和 y 值并将其命名为 j，然后在外部查询中您捕获这些值以使用另一个 SELECT 创建一个点，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）：db<>fiddle

演示（CTE）：db<>fiddle

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

关于您的查询的一些想法（无法看到全局）：

ST_AsText 在您的查询中绝对没有意义。你可以摆脱它。
请注意，您用于提取 x 和 y 坐标的代码是相同的，并且 ST_DumpPoints 已经 returns 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裂成不同值的相同点。

如何使用列的值作为空间操作的输入

how to use value of a column as input to a spatial operation

python

postgresql

postgis