关于MySQL数据库如何按时间查询

select * from simingpai where TIMESTAMP(createTime) >= ‘2015-9-6‘;
select * from simingpai where TIMESTAMP(createTime) >= ‘2015-9-6 00:00:00‘;
select * from simingpai where TIMESTAMP(createTime) >= ‘2015-9-6 18:15:00‘;
select * from simingpai where Date(createTime) >= ‘2015-9-6‘;
select * from simingpai where DATE(createTime) >= ‘2015-9-6 00:00:00‘;
select * from simingpai where DATE(createTime) >= ‘2015-9-6 00:00:01‘;
select * from simingpai where DATE(createTime) >= ‘2015-9-6 18:15:00‘;