docs: add docs for more geo functions

docs/reference/sql/functions/geo.md

@@ -7,6 +7,18 @@ are enabled when you have `common-function/geo` feature turned on (default: on).
 
 <TOCInline toc={toc} />
 
+## Geo Types
+
+Convert data between geospatial types.
+
+### `wkt_point_from_latlng`
+
+Convert latitude and longitude to WKT point.
+
+```sql
+SELECT wkt_point_from_latlng(37.76938, -122.3889) AS point;
+```
+
 ## Geohash
 
 See [more about geohash encoding
@@ -154,6 +166,23 @@ Arguments:
 h3_child_pos_to_cell(25, h3_latlng_to_cell(37.76938, -122.3889, 8), 11);
 ```
 
+### `h3_cells_contains`
+
+Return true if given cells contains cell, or cell's parent.
+
+Arguments:
+
+- cell set: it can be int64/uint64/string array, and comma-separated string cell
+  ID.
+- cell index: the cell to test
+
+```sql
+SELECT
+    h3_cells_contains('86283470fffffff,862834777ffffff, 862834757ffffff, 86283471fffffff, 862834707ffffff', '8b283470d112fff') AS R00,
+    h3_cells_contains(['86283470fffffff', '862834777ffffff', '862834757ffffff', '86283471fffffff', '862834707ffffff'], '8b283470d112fff') AS R11,
+    h3_cells_contains([604189641255419903, 604189643000250367, 604189642463379455, 604189641523855359, 604189641121202175], 604189641792290815) AS R21;
+```
+
 ### `h3_grid_disk`
 
 Returns cells with k distances of given cell.
@@ -207,6 +236,37 @@ FROM
     );
 ```
 
+### `h3_distance_sphere_km`
+
+Returns sphere distance between centroid of two cells, in km
+
+```sql
+SELECT
+    round(h3_distance_sphere_km(cell1, cell2), 5) AS sphere_distance
+FROM
+    (
+      SELECT
+          h3_string_to_cell('86283082fffffff') AS cell1,
+          h3_string_to_cell('86283470fffffff') AS cell2
+    );
+
+```
+
+### `h3_distance_degree`
+
+Returns euclidean distance between centroid of two cells, in degree.
+
+```sql
+SELECT
+    round(h3_distance_degree(cell1, cell2), 14) AS euclidean_distance
+FROM
+    (
+      SELECT
+          h3_string_to_cell('86283082fffffff') AS cell1,
+          h3_string_to_cell('86283470fffffff') AS cell2
+    );
+```
+
 ## S2
 
 Learn [more about S2 encoding](http://s2geometry.io/).
@@ -267,3 +327,125 @@ Example output:
 ```json
 [[-122.3888,37.77001],[-122.3839,37.76928],[-122.3889,37.76938],[-122.382,37.7693]]
 ```
+
+## Spatial Relation
+
+### `st_contains`
+
+Test spatial relationship between two objects: contains.
+
+Arguments: two spatial objects encoded with WKT.
+
+```sql
+SELECT
+    st_contains(polygon1, p1),
+    st_contains(polygon2, p1),
+FROM
+    (
+        SELECT
+            wkt_point_from_latlng(37.383287, -122.01325) AS p1,
+            'POLYGON ((-122.031661 37.428252, -122.139829 37.387072, -122.135365 37.361971, -122.057759 37.332222, -121.987707 37.328946, -121.943754 37.333041, -121.919373 37.349145, -121.945814 37.376705, -121.975689 37.417345, -121.998696 37.409164, -122.031661 37.428252))' AS polygon1,
+            'POLYGON ((-121.491698 38.653343, -121.582353 38.556757, -121.469721 38.449287, -121.315883 38.541721, -121.491698 38.653343))' AS polygon2,
+    );
+
+```
+
+### `st_within`
+
+Test spatial relationship between two objects: within.
+
+Arguments: two spatial objects encoded with WKT.
+
+```sql
+SELECT
+    st_within(p1, polygon1),
+    st_within(p1, polygon2),
+ ROM
+    (
+        SELECT
+            wkt_point_from_latlng(37.383287, -122.01325) AS p1,
+            'POLYGON ((-122.031661 37.428252, -122.139829 37.387072, -122.135365 37.361971, -122.057759 37.332222, -121.987707 37.328946, -121.943754 37.333041, -121.919373 37.349145, -121.945814 37.376705, -121.975689 37.417345, -121.998696 37.409164, -122.031661 37.428252))' AS polygon1,
+            'POLYGON ((-121.491698 38.653343, -121.582353 38.556757, -121.469721 38.449287, -121.315883 38.541721, -121.491698 38.653343))' AS polygon2,
+    );
+
+```
+
+
+### `st_intersects`
+
+Test spatial relationship between two objects: intersects.
+
+Arguments: two spatial objects encoded with WKT.
+
+```sql
+SELECT
+    st_intersects(polygon1, polygon2),
+    st_intersects(polygon1, polygon3),
+FROM
+    (
+        SELECT
+            'POLYGON ((-122.031661 37.428252, -122.139829 37.387072, -122.135365 37.361971, -122.057759 37.332222, -121.987707 37.328946, -121.943754 37.333041, -121.919373 37.349145, -121.945814 37.376705, -121.975689 37.417345, -121.998696 37.409164, -122.031661 37.428252))' AS polygon1,
+            'POLYGON ((-121.491698 38.653343, -121.582353 38.556757, -121.469721 38.449287, -121.315883 38.541721, -121.491698 38.653343))' AS polygon2,
+            'POLYGON ((-122.089628 37.450332, -122.20535 37.378342, -122.093062 37.36088, -122.044301 37.372886, -122.089628 37.450332))' AS polygon3,
+    );
+
+```
+
+
+## Spatial Measurement
+
+### `st_distance`
+
+Returns WGS84(SRID: 4326) euclidean distance between two geometry object, in
+degree.
+
+Arguments: two spatial objects encoded with WKT.
+
+```sql
+SELECT
+    st_distance(p1, p2) AS euclidean_dist,
+    st_distance(p1, polygon1) AS euclidean_dist_pp,
+FROM
+    (
+        SELECT
+            wkt_point_from_latlng(37.76938, -122.3889) AS p1,
+            wkt_point_from_latlng(38.5216, -121.4247) AS p2,
+            'POLYGON ((-121.491698 38.653343, -121.582353 38.556757, -121.469721 38.449287, -121.315883 38.541721, -121.491698 38.653343))' AS polygon1,
+    );
+```
+
+### `st_distance_sphere_m`
+
+Return great circle distance between two point, in meters.
+
+Arguments: two spatial objects encoded with WKT.
+
+```sql
+SELECT
+    st_distance_sphere_m(p1, p2) AS sphere_dist_m,
+FROM
+    (
+        SELECT
+            wkt_point_from_latlng(37.76938, -122.3889) AS p1,
+            wkt_point_from_latlng(38.5216, -121.4247) AS p2,
+    );
+
+```
+
+### `st_area`
+
+Returns area of given geometry object.
+
+Arguments: the spatial object encoded with WKT.
+
+```sql
+SELECT
+    st_area(p1) as area_point,
+    st_area(polygon1) as area_polygon,
+FROM
+    (
+        SELECT
+            wkt_point_from_latlng(37.76938, -122.3889) AS p1,
+            'POLYGON ((-121.491698 38.653343, -121.582353 38.556757, -121.469721 38.449287, -121.315883 38.541721, -121.491698 38.653343))' AS polygon1,
+    );
+```