ST_LongFromGeoHash(geohash_str)

Returns the longitude from a geohash string value, as a
double-precision number in the range [−180, 180].

The remarks in the description of ST_LatFromGeoHash() regarding the
maximum number of characters processed from the geohash_str argument
also apply to ST_LongFromGeoHash().

ST_LongFromGeoHash() handles its arguments as described in the
introduction to this section.

URL: https://dev.mysql.com/doc/refman/8.0/en/spatial-geohash-functions.html

