mysql如何实现排序

通过在数据表使用以下命令实现的排序

1.单列排序

SELECT * FROM test1 ORDER BY date_time

2.多列排序 

SELECT * FROM test1 ORDER BY `status`, date_time DESC

3.自定义排序

SELECT * FROM test1 ORDER BY FIELD(`status`, 3, 2, 4, 1, 5), date_time DESC

4.条件排序

SELECT * FROM test1 ORDER BY date_time < now if(date_time="">< now date_time),="" date_time="">