MySQL 9.4 Release Notes
        
      The ST_UNITS_OF_MEASURE table
      provides information about acceptable units for the
      ST_Distance() function.
    
      The ST_UNITS_OF_MEASURE table has
      these columns:
- UNIT_NAME- The name of the unit. 
- UNIT_TYPE- The unit type (for example, - LINEAR).
- CONVERSION_FACTOR- A conversion factor used for internal calculations. 
- DESCRIPTION- A description of the unit.