查询本月

where a.create_time between datetime('now','start of month','+1 second') and 

datetime('now','start of month','+1 month','-1 second')

查询多少天之内

where julianday(datetime('now','localtime'))-julianday(a.create_time) <300

这明白的就是和sqlserver 干啊  连个datediff都没有