infludb语法--官网

https://docs.influxdata.com/influxdb/v0.8/api/query_language/

InfluxDB features a SQL like query language,only used for querying data. The HTTP API has endpoints for writing data and performing other database administration tasks. The only exception to this is?,which perpetually write their results into one or more time series.

InfluxDB allows you to use any characters in your time series names. However,parsing queries for those series can be tricky. So it’s best to wrap your queries for any series that has characters other than letters in double quotes like this:

select * from "series with "double quotes""

<h2 id="">
<a id="getting-a-list-of-time-series" class="offset-anchor"><a href="https://docs.influxdata.com/influxdb/v0.8/api/query_language/#getting-a-list-of-time-series"&gt;Getting a List of Time Series

There are two different methods for returning a list of all time series in a database:

The first query will return all series,while the second will return the most recent point from each series that matches the given regex.

By default,InfluxDB returns data in time descending order. The most efficient queries run over only a single column in a given time series.

This simple query pulls the values for the?value?column from the?response_times?series.

If start and end times aren’t set they will default to beginning of time until now,respectively.

The column?time?is built in for every time series in the database. You specify the start and end times by setting conditions on the?time?columns in the where clause.

Below are the different formats that can be used to specify start and end times.

Date time strings have the format?YYYY-MM-DD HH:MM:SS.mmm?where?mmm?are the milliseconds within the second. For example:

 '2013-08-12 23:32:01.232' and time < '2013-08-13';

The time and date should be wrapped in single quotes. If you only specify the date,the time will be set to?00:00:00. The?.232?after the hours,minutes,and seconds is optional and specifies the milliseconds.

You can use?now()?to calculate a timestamp relative to the server’s current timestamp. For example:

 now() - 1h limit 1000;

will return all points starting an hour ago until now.

Other options for how to specify time durations are?u?for microseconds,?s?for seconds,?m?for minutes,?h?for hours,?d?for days and?w?for weeks. If no suffix is given the value is interpreted as microseconds.

You can specify timestamp in epoch time,which is defined as the number of microseconds that have elapsed since 00:00:00 Coordinated Universal Time (UTC),Thursday,1 January 1970. You can use the same suffixes from the previous section if you don’t want to specify timestamp in microseconds. For example:

 1388534400s

will return all points that were writtern after?2014-01-01 00:00:00

Points are uniquely identified by the time series they appear in,the time,and the sequence number. Here’s a query that returns a specific point.

Note?that the time is a very large number. That’s because it’s a microsecond scale epoch. InfluxDB always stores points at this scale,but most libraries will return the time as either a second,or millisecond scale value. If you’re selecting a specific point,you’ll need to know the exact microsecond scale epoch that point has otherwise you’ll get an unexpected empty result.

You can select from multiple series by name or by specifying a regex to match against. Here are a few examples.

Get the last hour of data from the two series?events,and?errors. Here’s a regex example:

 now() - 1h;

Get the last hour of data from every time series that starts with?stats.?(case insensitive). Another example:

Return the last point from every time series in the database.

The delete query looks like the following:

With no time constraints this query will delete every point in the time series?response_times. You must be a cluster or database admin to run delete queries.

You can also delete from any series that matches a regex:

Any conditions in the where clause that don’t set the start and/or end time will be ignored,for example the following query returns an error:

Delete time conditions only support ranges,an equals condition (=) is currently not supported.

Deleting all data for a series will only remove the points. It will still remain in the index. If you want to remove all data from a series and remove it from the list of series in a database use the?drop?query:

Currently,deletes are not very efficient. If you want to quickly evict old data,the best way to do that is by dropping a shard. For more?.

We’ve already seen the where clause for selecting time ranges and a specific point. You can also use it to filter based on given values,comparators,or regexes. Here are some examples of different ways to use?where.

select * from log_lines where line =~ /error/i;

select * from events where customer_id = 23 and type = 'click';
select * from response_times where value > 500;
select  from events where email !~ /.gmail.*/;
select * from nagios_checks where status <> 0;
select * from events where signed_in = false;
select  from events

where (email =~ /.gmail./ or email =~ /.yahoo.*/) and state = 'ny';

The where clause supports comparisons against regexes,strings,booleans,floats,integers,and the times listed before. Comparators include?=?equal to,?>?greater than,?<?less than,?<>?not equal to,?=~?matches against,?!~?doesn’t match against. You can chain logic together using?and?and?or?and you can separate using?(?and?)

The group by clause in InfluxDB is used not only for grouping by given values,but also for grouping by given time buckets. You’ll always be pairing this up with??in the?select?clause. Here are a few examples to illustrate how group by works.

-- count of each unique type of event in 10 minute intervals

select count(type) from events group by time(10m),type;

-- 95th percentile of response times in 30 second intervals

select percentile(value,95) from response_times group by time(30s);

By default functions will output a column that have the same name as the function,e.g.?count?will output a column with the name?count?in order to change the name of the column an?AS?clause is required. Here is an example to illustrate how aliasing work:

The time function takes the time interval which can be in microseconds,seconds,hours,days or weeks. To specify the units you can use the respective suffix?u,?s,?m,?h,?d?and?w.

By default,group by intervals that have no data will not have associated datapoints. For instance,say you have the following query:

 now() - 3h

If the events series had data for this hour and two hours ago only,you’d only get two points in the result. If you want to ensure that you get back points for intervals that don’t have data,you can use the?fill?function. Any numerical value,including negative values,and the special value?null,are valid values for?fill. For example,each of the following queries is valid:

 now() - 3h

 now() - 3h

 now() - 3h

Note that?fill?must go at the end of the group by clause if there are other arguments:

 now() - 3h

You can merge multiple time series into a single stream in the select clause. This is helpful when you want to run a function over one of the columns with an associated group by time clause.

You’d get a single time series with the count of events from the two combined in 10 minute intervals.

Joins will put two or more series together. Since timestamps may not match exactly,InfluxDB will make a best effort to put points together. Joins are used when you want to perform a transformation of one time series against another. Here are a few examples.

The above query will return a time series of the combined cpu load for hosts a and b. The individual points will be coerced into the closest time frames to match up.

The above query will return the error rate per minute.

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