USE accounting;
set sql_log_bin=0;

ALTER TABLE accounting.cdr 
MODIFY source_carrier_cost       decimal(14,6) DEFAULT NULL,
MODIFY source_reseller_cost      decimal(14,6) DEFAULT NULL,
MODIFY source_customer_cost      decimal(14,6) DEFAULT NULL,
MODIFY destination_carrier_cost  decimal(14,6) DEFAULT NULL,
MODIFY destination_reseller_cost decimal(14,6) DEFAULT NULL,
MODIFY destination_customer_cost decimal(14,6) DEFAULT NULL;