GaussDB-几何函数和操作符GaussDB-几何函数和操作符几何操作符描述：平移。示例：

GaussDB-几何函数和操作符

几何操作符

描述：平移。

示例：

| ``` gaussdb=# SELECT box '((0,0),(1,1))' + point '(2.0,0)' AS RESULT; result ------------- (3,1),(2,0) (1 row)
```
| --------------------------------------------------------------------------------------------------------------------------- |
```
描述：平移。

示例：

| ``` gaussdb=# SELECT box '((0,0),(1,1))' - point '(2.0,0)' AS RESULT; result --------------- (-1,1),(-2,0) (1 row)
```
| --------------------------------------------------------------------------------------------------------------------------------- |
```
描述：伸展/旋转。

示例：

| ``` gaussdb=# SELECT box '((0,0),(1,1))' * point '(2.0,0)' AS RESULT; result ------------- (2,2),(0,0) (1 row)
```
| --------------------------------------------------------------------------------------------------------------------------- |
```
/

描述：收缩/旋转。

示例：

| ``` gaussdb=# SELECT box '((0,0),(2,2))' / point '(2.0,0)' AS RESULT; result ------------- (1,1),(0,0) (1 row)
```
| --------------------------------------------------------------------------------------------------------------------------- |
```
描述：两个图形交面。

示例：

| ``` gaussdb=# SELECT box '((1,-1),(-1,1))' # box '((1,1),(-2,-2))' AS RESULT; result --------------- (1,1),(-1,-1) (1 row)
```
| ---------------------------------------------------------------------------------------------------------------------------------- |
```
描述：图形的路径数目或多边形顶点数。

示例：

| ``` gaussdb=# SELECT # path'((1,0),(0,1),(-1,0))' AS RESULT; result -------- 3 (1 row)
```
| --------------------------------------------------------------------------------------------------- |
```
@-@

描述：图形的长度或者周长。

示例：

| ``` gaussdb=# SELECT @-@ path '((0,0),(1,0))' AS RESULT; result -------- 2 (1 row)
```
| ----------------------------------------------------------------------------------------------- |
```
@@

描述：图形的中心。

示例：

| ``` gaussdb=# SELECT @@ circle '((0,0),10)' AS RESULT; result -------- (0,0) (1 row)
```
| -------------------------------------------------------------------------------------------- |
```
<->

描述：两个图形之间的距离。

示例：

| ``` gaussdb=# SELECT circle '((0,0),1)' <-> circle '((5,0),1)' AS RESULT; result -------- 3 (1 row)
```
| ---------------------------------------------------------------------------------------------------------------- |
```
&&

描述：两个图形是否重叠（有一个共同点就为真）。

示例：

| ``` gaussdb=# SELECT box '((0,0),(1,1))' && box '((0,0),(2,2))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------------ |
```
<<

描述：图形是否全部在另一个图形的左边（没有相同的横坐标）。

示例：

| ``` gaussdb=# SELECT circle '((0,0),1)' << circle '((5,0),1)' AS RESULT; result -------- t (1 row)
```
| ---------------------------------------------------------------------------------------------------------- |
```
描述：图形是否全部在另一个图形的右边（没有相同的横坐标）。

示例：

| ``` gaussdb=# SELECT circle '((5,0),1)' >> circle '((0,0),1)' AS RESULT; result -------- t (1 row)
```
| ---------------------------------------------------------------------------------------------------------- |
```
&<

描述：图形的最右边是否不超过在另一个图形的最右边。

示例：

| ``` gaussdb=# SELECT box '((0,0),(1,1))' &< box '((0,0),(2,2))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------------ |
```
&>

描述：图形的最左边是否不超过在另一个图形的最左边。

示例：

| ``` gaussdb=# SELECT box '((0,0),(3,3))' &> box '((0,0),(2,2))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------------ |
```
<<|

描述：图形是否全部在另一个图形的下边（没有相同的纵坐标）。

示例：

| ``` gaussdb=# SELECT box '((0,0),(3,3))' <<| box '((3,4),(5,5))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------------- |
```
|>>

描述：图形是否全部在另一个图形的上边（没有相同的纵坐标）。

示例：

| ``` gaussdb=# SELECT box '((3,4),(5,5))' |>> box '((0,0),(3,3))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------------- |
```
&<|

描述：图形的最上边是否不超过另一个图形的最上边。

示例：

| ``` gaussdb=# SELECT box '((0,0),(1,1))' &<| box '((0,0),(2,2))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------------- |
```
|&>

描述：图形的最下边是否不超过另一个图形的最下边。

示例：

| ``` gaussdb=# SELECT box '((0,0),(3,3))' |&> box '((0,0),(2,2))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------------- |
```
<^

描述：图形是否低于另一个图形（允许两个图形有接触）。

示例：

| ``` gaussdb=# SELECT box '((0,0),(-3,-3))' <^ box '((0,0),(2,2))' AS RESULT; result -------- t (1 row)
```
| -------------------------------------------------------------------------------------------------------------- |
```
^

描述：图形是否高于另一个图形（允许两个图形有接触）。

示例：

| ``` gaussdb=# SELECT box '((0,0),(2,2))' >^ box '((0,0),(-3,-3))' AS RESULT; result -------- t (1 row)
```
| --------------------------------------------------------------------------------------------------------------- |
```
?#

描述：两个图形是否相交。

示例：

| ``` gaussdb=# SELECT lseg '((-1,0),(1,0))' ?# box '((-2,-2),(2,2))' AS RESULT; result -------- t (1 row)
```
| ---------------------------------------------------------------------------------------------------------------- |
```
?-

描述：图形是否处于水平位置。

示例：

| ``` gaussdb=# SELECT ?- lseg '((-1,0),(1,0))' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------ |
```
?-

描述：图形是否水平对齐。

示例：

| ``` gaussdb=# SELECT point '(1,0)' ?- point '(0,0)' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------ |
```
?|

描述：图形是否处于竖直位置。

示例：

| ``` gaussdb=# SELECT ?| lseg '((-1,0),(1,0))' AS RESULT; result -------- f (1 row)
```
| ------------------------------------------------------------------------------------------ |
```
?|

描述：图形是否竖直对齐。

示例：

| ``` gaussdb=# SELECT point '(0,1)' ?| point '(0,0)' AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------ |
```
?-|

描述：两条线是否垂直。

示例：

| ``` gaussdb=# SELECT lseg '((0,0),(0,1))' ?-| lseg '((0,0),(1,0))' AS RESULT; result -------- t (1 row)
```
| --------------------------------------------------------------------------------------------------------------- |
```
?||

描述：两条线是否平行。

示例：

| ``` gaussdb=# SELECT lseg '((-1,0),(1,0))' ?|| lseg '((-1,2),(1,2))' AS RESULT; result -------- t (1 row)
```
| ----------------------------------------------------------------------------------------------------------------- |
```
@>

描述：图形是否包含另一个图形。

示例：

| ``` gaussdb=# SELECT circle '((0,0),2)' @> point '(1,1)' AS RESULT; result -------- t (1 row)
```
| ----------------------------------------------------------------------------------------------------- |
```
<@

描述：图形是否被包含于另一个图形。

示例：

| ``` gaussdb=# SELECT point '(1,1)' <@ circle '((0,0),2)' AS RESULT; result -------- t (1 row)
```
| ----------------------------------------------------------------------------------------------------- |
```
~=

描述：两个图形是否相同。

示例：

| ``` gaussdb=# SELECT polygon '((0,0),(1,1))' ~= polygon '((1,1),(0,0))' AS RESULT; result -------- t (1 row)
```
| -------------------------------------------------------------------------------------------------------------------- |
```

几何函数

area(object)

描述：计算图形的面积。

返回类型：double precision

示例：

| ``` gaussdb=# SELECT area(box '((0,0),(1,1))') AS RESULT; result -------- 1 (1 row)
```
| ------------------------------------------------------------------------------------------------ |
```
center(object)

描述：计算图形的中心。

返回类型：point

示例：

| ``` gaussdb=# SELECT center(box '((0,0),(1,2))') AS RESULT; result --------- (0.5,1) (1 row)
```
| ----------------------------------------------------------------------------------------------------- |
```
diameter(circle)

描述：计算圆的直径。

返回类型：double precision

示例：

| ``` gaussdb=# SELECT diameter(circle '((0,0),2.0)') AS RESULT; result -------- 4 (1 row)
```
| ----------------------------------------------------------------------------------------------------- |
```
height(box)

描述：矩形的竖直高度。

返回类型：double precision

示例：

| ``` gaussdb=# SELECT height(box '((0,0),(1,1))') AS RESULT; result -------- 1 (1 row)
```
| -------------------------------------------------------------------------------------------------- |
```
isclosed(path)

描述：图形是否为闭合路径。

返回类型：Boolean

示例：

| ``` gaussdb=# SELECT isclosed(path '((0,0),(1,1),(2,0))') AS RESULT; result -------- t (1 row)
```
| ------------------------------------------------------------------------------------------------------ |
```
isopen(path)

描述：图形是否为开放路径。

返回类型：Boolean

示例：

| ``` gaussdb=# SELECT isopen(path '[(0,0),(1,1),(2,0)]') AS RESULT; result -------- t (1 row)
```
| ---------------------------------------------------------------------------------------------------- |
```
length(object)

描述：计算图形的长度。

返回类型：double precision

示例：

| ``` gaussdb=# SELECT length(path '((-1,0),(1,0))') AS RESULT; result -------- 4 (1 row)
```
| ---------------------------------------------------------------------------------------------------- |
```
npoints(path)

描述：计算路径的顶点数。

返回类型：int

示例：

| ``` gaussdb=# SELECT npoints(path '[(0,0),(1,1),(2,0)]') AS RESULT; result -------- 3 (1 row)
```
| ---------------------------------------------------------------------------------------------------------- |
```
npoints(polygon)

描述：计算多边形的顶点数。

返回类型：int

示例：

| ``` gaussdb=# SELECT npoints(polygon '((1,1),(0,0))') AS RESULT; result -------- 2 (1 row)
```
| ------------------------------------------------------------------------------------------------------- |
```
pclose(path)

描述：把路径转换为闭合路径。

返回类型：path

示例：

| ``` gaussdb=# SELECT pclose(path '[(0,0),(1,1),(2,0)]') AS RESULT; result --------------------- ((0,0),(1,1),(2,0)) (1 row)
```
| ------------------------------------------------------------------------------------------------------------------------------------------------ |
```
popen(path)

描述：把路径转换为开放路径。

返回类型：path

示例：

| ``` gaussdb=# SELECT popen(path '((0,0),(1,1),(2,0))') AS RESULT; result --------------------- [(0,0),(1,1),(2,0)] (1 row)
```
| ----------------------------------------------------------------------------------------------------------------------------------------------- |
```
radius(circle)

描述：计算圆的半径。

返回类型：double precision

示例：

| ``` gaussdb=# SELECT radius(circle '((0,0),2.0)') AS RESULT; result -------- 2 (1 row)
```
| --------------------------------------------------------------------------------------------------- |
```
width(box)

描述：计算矩形的水平尺寸。

返回类型：double precision

示例：

| ``` gaussdb=# SELECT width(box '((0,0),(1,1))') AS RESULT; result -------- 1 (1 row)
```
| ------------------------------------------------------------------------------------------------- |
```

几何类型转换函数

box(circle)

描述：将圆转换成矩形。

返回类型：box

示例：

| ``` gaussdb=# SELECT box(circle '((0,0),2.0)') AS RESULT; result --------------------------------------------------------------------------- (1.41421356237309,1.41421356237309),(-1.41421356237309,-1.41421356237309) (1 row)
```
| --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
```
box(point, point)

描述：将点转换成矩形。

返回类型：box

示例：

| ``` gaussdb=# SELECT box(point '(0,0)', point '(1,1)') AS RESULT; result ------------- (1,1),(0,0) (1 row)
```
| ----------------------------------------------------------------------------------------------------------------------- |
```
box(polygon)

描述：将多边形转换成矩形。

返回类型：box

示例：

| ``` gaussdb=# SELECT box(polygon '((0,0),(1,1),(2,0))') AS RESULT; result ------------- (2,1),(0,0) (1 row)
```
| ------------------------------------------------------------------------------------------------------------------------ |
```
circle(box)

描述：矩形转换成圆。

返回类型：circle

示例：

| ``` gaussdb=# SELECT circle(box '((0,0),(1,1))') AS RESULT; result ------------------------------- <(0.5,0.5),0.707106781186548> (1 row)
```
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
```
circle(point, double precision)

描述：将圆心和半径转换成圆。

返回类型：circle

示例：

| ``` gaussdb=# SELECT circle(point '(0,0)', 2.0) AS RESULT; result ----------- <(0,0),2> (1 row)
```
| ---------------------------------------------------------------------------------------------------------- |
```
circle(polygon)

描述：将多边形转换成圆。

返回类型：circle

示例：

| ``` gaussdb=# SELECT circle(polygon '((0,0),(1,1),(2,0))') AS RESULT; result ------------------------------------------- <(1,0.333333333333333),0.924950591148529> (1 row)
```
| --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
```
lseg(box)

描述：矩形对角线转化成线段。

返回类型：lseg

示例：

| ``` gaussdb=# SELECT lseg(box '((-1,0),(1,0))') AS RESULT; result ---------------- [(1,0),(-1,0)] (1 row)
```
| ------------------------------------------------------------------------------------------------------------------------- |
```
lseg(point, point)

描述：点转换成线段。

返回类型：lseg

示例：

| ``` gaussdb=# SELECT lseg(point '(-1,0)', point '(1,0)') AS RESULT; result ---------------- [(-1,0),(1,0)] (1 row)
```
| ---------------------------------------------------------------------------------------------------------------------------------- |
```

slope(point, point)

描述：计算两个点构成直线的斜率。

返回类型：double

示例：

gaussdb=# SELECT slope(point '(1,1)', point '(0,0)') AS RESULT;
 result
--------
      1
(1 row)

path(polygon)

描述：多边形转换成路径。

返回类型：path

示例：

| ``` gaussdb=# SELECT path(polygon '((0,0),(1,1),(2,0))') AS RESULT; result --------------------- ((0,0),(1,1),(2,0)) (1 row)
```
| ------------------------------------------------------------------------------------------------------------------------------------------------- |
```
point(double precision, double precision)

描述：节点。

返回类型：point

示例：

| ``` gaussdb=# SELECT point(23.4, -44.5) AS RESULT; result -------------- (23.4,-44.5) (1 row)
```
| ----------------------------------------------------------------------------------------------------------- |
```
point(box)

描述：矩形的中心。

返回类型：point

示例：

| ``` gaussdb=# SELECT point(box '((-1,0),(1,0))') AS RESULT; result -------- (0,0) (1 row)
```
| ------------------------------------------------------------------------------------------------- |
```
point(circle)

描述：圆心。

返回类型：point

示例：

| ``` gaussdb=# SELECT point(circle '((0,0),2.0)') AS RESULT; result -------- (0,0) (1 row)
```
| ------------------------------------------------------------------------------------------------- |
```
point(lseg)

描述：线段的中心。

返回类型：point

示例：

| ``` gaussdb=# SELECT point(lseg '((-1,0),(1,0))') AS RESULT; result -------- (0,0) (1 row)
```
| -------------------------------------------------------------------------------------------------- |
```
point(polygon)

描述：多边形的中心。

返回类型：point

示例：

| ``` gaussdb=# SELECT point(polygon '((0,0),(1,1),(2,0))') AS RESULT; result ----------------------- (1,0.333333333333333) (1 row)
```
| -------------------------------------------------------------------------------------------------------------------------------------------------------- |
```
polygon(box)

描述：矩形转换成4点多边形。

返回类型：polygon

示例：

| ``` gaussdb=# SELECT polygon(box '((0,0),(1,1))') AS RESULT; result --------------------------- ((0,0),(0,1),(1,1),(1,0)) (1 row)
```
| ------------------------------------------------------------------------------------------------------------------------------------------------------------ |
```
polygon(circle)

描述：圆转换成12点多边形。

返回类型：polygon

示例：

| ``` gaussdb=# SELECT polygon(circle '((0,0),2.0)') AS RESULT; result ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ((-2,0),(-1.73205080756888,1),(-1,1.73205080756888),(-1.22464679914735e-16,2),(1,1.73205080756888),(1.73205080756888,1),(2,2.44929359829471e-16),(1.73205080756888,-0.999999999999999),(1,-1.73205080756888),(3.67394039744206e-16,-2),(-0.999999999999999,-1.73205080756888),(-1.73205080756888,-1)) (1 row)
```
| --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
```
polygon(npts, circle)

描述：圆转换成npts点多边形。

返回类型：polygon

示例：

| ``` gaussdb=# SELECT polygon(12, circle '((0,0),2.0)') AS RESULT; result ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ((-2,0),(-1.73205080756888,1),(-1,1.73205080756888),(-1.22464679914735e-16,2),(1,1.73205080756888),(1.73205080756888,1),(2,2.44929359829471e-16),(1.73205080756888,-0.999999999999999),(1,-1.73205080756888),(3.67394039744206e-16,-2),(-0.999999999999999,-1.73205080756888),(-1.73205080756888,-1)) (1 row)
```
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
```
polygon(path)

描述：路径转换成多边形。

返回类型：polygon

示例：

| ``` gaussdb=# SELECT polygon(path '((0,0),(1,1),(2,0))') AS RESULT; result --------------------- ((0,0),(1,1),(2,0)) (1 row)
```
| ------------------------------------------------------------------------------------------------------------------------------------------------- |
```

更多详情请参考GaussDB 文档中心：doc.hcs.huawei.com/db/zh-cn/ga…