 """
\n
SELECT *\n
FROM `#__gdwgestion_servicepoint`\n
WHERE CalculateDistance(, , `lat`, `lng`)<=50 AND `published`=1\n
ORDER BY CalculateDistance(, , `lat`, `lng`) ASC,`ordering` ASC
"""

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ' , `lat`, `lng`)<=50 AND `published`=1 ORDER BY CalculateDistance(, , `lat`, ...' at line 3