判断表中一个字段是否存在的方法：
语法：
select count(*) from information_schema.columns where table_name = '表名' and column_name = '字段名'
sql例子：
select count(*) from information_schema.columns where table_name = 't_iov_vehicle_owner_info' and column_name = 'id'
推荐：MySQL教程
