选择每小时查询
我有一个简单的气象站数据库，其中包含示例内容:
I have a simple weather station DB with example content:
time humi1 humi2 light pressure station-id temp1 temp2
---- ----- ----- ----- -------- ---------- ----- -----
1530635257289147315 66 66 1834 1006 bee1 18.6 18.6
1530635317385229860 66 66 1832 1006 bee1 18.6 18.6
1530635377466534866 66 66 1829 1006 bee1 18.6 18.6
Station每分钟写入一次数据.我不希望所有系列都获得SELECT，而是每个小时(或者说第60个系列，简而言之)编写的系列.我该如何实现?
Station writes data every minute. I want to get SELECT not with all series, but just series written every hour (or every 60th series, simply said). How can I achieve it?
我尝试使用...WHERE time % 60 = 0进行实验，但是没有用.似乎time列不允许任何数学运算(/，%等).
I tried to experiment with ...WHERE time % 60 = 0, but it didn`t work. It seems, that time column doesnt permit any math operations (/, %, etc).
Group by和其中一个功能可以完成您想要的操作:
Group by along with a one of the functions can do what you want:
SELECT FIRST("humi1"), FIRST("humi2"), ... GROUP BY time(1h)
我想对于大多数气候数据来说，您希望使用MEAN或MEDIAN，而不是每小时都需要一个数据点
I would imagine for most climate data you'd want the MEAN or MEDIAN rather than a single data point every hour