SQL Accounting and Null Attribute Values

[trs]

Accounting queries fail if an attribute is null when supplied as a
value for certain column types.
Partial line from debug output:

radius_xlat: 'UPDATE radacct SET AcctStartTime = '2006-03-02
01:18:04', AcctStartDelay = '',

It fails with:

rlm_sql (sql): Couldn't update SQL accounting START record - ERROR: 
invalid input syntax for type bigint: ""

Can freeradius substitute a zero if an integer attribute is missing
from an accounting packet, instead of just a null value?