intervals

问题 I have a SQL below which is able to get the interval average of timestamp column grouped by icao_address, flight_number, flight_date. I'm trying to do the same for standard deviation and although I get a figure, it is wrong. The standard deviation that I get back is 14.06 (look at image below to see) while it should be around 1.8. Below is what I'm using for stddev calculation. STDDEV_POP(UNIX_SECONDS(timestamp))as standard_deviation Below is my SQL #standardSQL select DATE(timestamp) as

问题 I have a SQL below which is able to get the interval average of timestamp column grouped by icao_address, flight_number, flight_date. I'm trying to do the same for standard deviation and although I get a figure, it is wrong. The standard deviation that I get back is 14.06 (look at image below to see) while it should be around 1.8. Below is what I'm using for stddev calculation. STDDEV_POP(UNIX_SECONDS(timestamp))as standard_deviation Below is my SQL #standardSQL select DATE(timestamp) as

问题 I have a SQL below which is able to get the interval average of timestamp column grouped by icao_address, flight_number, flight_date. I'm trying to do the same for standard deviation and although I get a figure, it is wrong. The standard deviation that I get back is 14.06 (look at image below to see) while it should be around 1.8. Below is what I'm using for stddev calculation. STDDEV_POP(UNIX_SECONDS(timestamp))as standard_deviation Below is my SQL #standardSQL select DATE(timestamp) as

问题 I'm trying to group the variable according to its values and get a histogram. For example, this is my data: r <-c(1,899,1,2525,763,3,2,2,1863,695,9,4,2876,1173,1156,5098,3,3876,1,1, 3023,76336,13,003,9898,1,10,843,10546,617,1375,1,1,5679,1,21,1,13,6,28,1,14088,682) I want to group r by its value, like: 1-5, 5-10, 10-100, 100-500 and more than 500. And then I want to get a histogram which the x axis is in the type of interval (1-5,5-10,10-100,100-500 and more than 500) . How to solve that? If

问题 This answer has shown me how to get annual changes from data: UPDATE values_table as a join values_table as b ON b.date_sampled = DATE_SUB(a.date_sampled, INTERVAL 1 YEAR) set a.annual_change = a.sample_value - b.sample_value And this answer has shown me how to find the closest date to an INTERVAL (relative to NOW() with 3 results, in this question's case): SELECT event_id FROM Table ORDER BY ABS( DATEDIFF( EVENT_START_DATE, NOW() ) ) LIMIT 3 How can the two be combined to get annual rates of

问题 This answer has shown me how to get annual changes from data: UPDATE values_table as a join values_table as b ON b.date_sampled = DATE_SUB(a.date_sampled, INTERVAL 1 YEAR) set a.annual_change = a.sample_value - b.sample_value And this answer has shown me how to find the closest date to an INTERVAL (relative to NOW() with 3 results, in this question's case): SELECT event_id FROM Table ORDER BY ABS( DATEDIFF( EVENT_START_DATE, NOW() ) ) LIMIT 3 How can the two be combined to get annual rates of

问题 I’m using Postgres 9. I’m trying to do date math with a column in my table that is an integer. I’m trying this: select current_timestamp + interval age || ' years' from my_table where age is not null limit 5; ERROR: syntax error at or near "||" LINE 1: select current_timestamp + interval age || ' years' from rac... What is the proper way to write this? I’m trying to add the age column, which is in years, to the current timestamp (now)? 回答1: Multiply your integer with 1-year intervals and add

问题 Basically, this question is an extension of this one: Create monthly mean by time intervals Now I have temperature observations from five different sources, and I would like to apply the same logic on all of them: calculate a data interval average for each of the columns (except for the last, which should be kept untouched). First, what I need to do is to average all januaries, februaries, marches and etc for the whole period. Then, I would like to do the same for specific periods of time (3

问题 is it possible to cast as an interval in MySQL? I want to evaluate a value from the query as an interval, like this: select DATE_SUB(NOW(),CAST(user.expiry_interval AS interval)) where user.expiry_interval is 'INTERVAL 1 WEEK' or something like that select DATE_SUB(NOW(),CAST('INTERVAL 1 week' AS INTERVAL)) 回答1: INTERVAL is not a data type, but a keyword that converts a human-readable "duration" string into an integer. As such, "casting to INTERVAL " makes no sense. If your "interval" input

问题 I was working on google's activity recognition and finally I got results from this service. However, The function requestActivityUpdates(long detectionIntervalMillis, PendingIntent callbackIntent) doesn't seem to work correctly. The detection interval is not regular and decreases to 30~50 seconds when my current activity is changing. It doesn't work like the live demo on google I/O 2013 (Google I/O 2013 Location API, from 27:47 to 28:45). Does anyone have same issue on it? 回答1: Well it's a