I was never able with MySQL. I posted about it here Issues with using ODBC to query json response from MySQL. From my limited knowledge of how software interacts with DB’s is it allocates enough memory for the max value of a column. So if say you have a column that is varchar(10) then the code will allocate a minimum for 10 characters. I suspect (this is just a hunch) that my issue is related to Asterisk not knowing/allocating the correct amount of memory.