Categories:: Geospatial functions

H3_TRY_GRID_DISTANCE¶

A special version of H3_GRID_DISTANCE that returns NULL if an error occurs when it attempts to return the distance between two H3 cells.

语法

H3_TRY_GRID_DISTANCE( <cell_id_1> , <cell_id_2> )

实参

cell_id_1: An INTEGER value that represents the H3 cell ID (index (https://h3geo.org/docs/core-library/h3Indexing)), or a VARCHAR value that represents the cell ID in hexadecimal format.
cell_id_2: An INTEGER value that represents the H3 cell ID (index (https://h3geo.org/docs/core-library/h3Indexing)), or a VARCHAR value that represents the cell ID in hexadecimal format.

返回一个 INTEGER 值或 NULL。

If the function can perform a successful calculation, returns the INTEGER value that represents the distance in grid cells between the two H3 cells.
If the grid distance cannot be calculated (for example, when two cells belong to non-neighboring base cells (https://h3geo.org/docs/library/index/cell/)), returns NULL without reporting an error.

使用说明

See H3_GRID_DISTANCE for the usage notes.

示例

以下示例尝试计算两个单元格之间的距离。由于单元格属于非相邻的基本单元格，因此该函数无法计算距离并返回 NULL。

SELECT H3_TRY_GRID_DISTANCE(582046271372525567, 581883543651614719);

+--------------------------------------------------------------+
| H3_TRY_GRID_DISTANCE(582046271372525567, 581883543651614719) |
%--------------------------------------------------------------%
|                                                         NULL |
+--------------------------------------------------------------+

For examples that successfully calculate the distance between two H3 cells, see H3_GRID_DISTANCE.