SQL统计一个字段里某个特定字符的个数

select sum(length(couponrecordid)-length(replace(couponrecordid,',',''))) from t_order where paytype=2 and (studentstate!=4 and coachstate!=4)

and couponrecordid  like '%,%';

其中：couponrecordid 字段中的值：

12,566

67,45,88,99

134,7,8,9,678