通过sql一步处理
insert into table_name(column1,column2,column3)
select ‘value1‘,‘value2‘,‘value3‘
where not exists(select column from table_name where id=1);
eg：
insert into subscribe_member(openid,msg_title,can_times)
select ‘hhhh‘,‘biaoti‘,1
where not exists(select openid from subscribe_member where id=1);