> SELECT "water_level" FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2015-08-18T00:00:00Z' AND time <= '2015-08-18T00:30:00Z'name: h2o_feet
time water_level
---- -----------
2015-08-18T00:00:00Z 2.064
2015-08-18T00:06:00Z 2.116
2015-08-18T00:12:00Z 2.028
2015-08-18T00:18:00Z 2.126
2015-08-18T00:24:00Z 2.041
2015-08-18T00:30:00Z 2.051
# unit为默认的1秒
> SELECT INTEGRAL("water_level") FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2015-08-18T00:00:00Z' AND time <= '2015-08-18T00:30:00Z'name: h2o_feet
time integral
---- --------
1970-01-01T00:00:00Z 3732.66# unit为1分
> SELECT INTEGRAL("water_level", 1m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2015-08-18T00:00:00Z' AND time <= '2015-08-18T00:30:00Z'name: h2o_feet
time integral
---- --------
1970-01-01T00:00:00Z 62.211
> SELECT SPREAD("water_level") FROM "h2o_feet" WHERE time >= '2015-08-17T23:48:00Z' AND time <= '2015-08-18T00:30:00Z' GROUP BY time(12m),* fill(18) LIMIT 3 SLIMIT 1 SOFFSET 1
name: h2o_feet
tags: location=santa_monica
time spread
---- ------
2015-08-17T23:48:00Z 18
2015-08-18T00:00:00Z 0.052000000000000046
2015-08-18T00:12:00Z 0.09799999999999986
> SELECT STDDEV("water_level") FROM "h2o_feet" WHERE time >= '2015-08-17T23:48:00Z' AND time <= '2015-08-18T00:30:00Z' GROUP BY time(12m),* fill(18) SLIMIT 1;
name: h2o_feet
tags: location=coyote_creek
time stddev
---- ------
2015-08-17T23:48:00Z 18
2015-08-18T00:00:00Z 0.08131727983645186
2015-08-18T00:12:00Z 0.08838834764831845
2015-08-18T00:24:00Z 0.09545941546018377
如果一共有4条记录,N为10,则10%*4=0.4,四舍五入为0,则查询结果为空。N为20,则 20% * 4 = 0.8,四舍五入为1,选取的是4个数中最小的数。如果N为40,40% * 4 = 1.6,四舍五入为2,则选取的是4个数中第二小的数。由此可以看出N=100时,就跟MAX(field_key)
是一样的,而当N=50时,与MEDIAN(field_key)
在字段值为奇数个时是一样的。
> SELECT PERCENTILE("water_level",20) FROM "h2o_feet" WHERE time >= '2015-08-17T23:48:00