db随机值

oracle: select * from table_name order by dbms_random.value

#扫描记录时给每条记录生成一个随机值，然后根据这个值进行排序
mssql: select top N * from table_name order by newid()

mysql: select * from table_name order by rand()
#mysql用随机值更新记录
update articles set views = rand()* 1000

sqlite3: select * from table_name order by random()