influxdb/QUERIES.md

The top level name is called a measurement. These names can contain any characters. Then there are field names, field values, tag keys and tag values, which can also contain any characters. Because of this, anywhere a measurement name, field name, field value, tag name, or tag value appears should be able to get wrapped in double quotes to deal with special characters.

# Databases & retention policies

```sql
-- create a database
CREATE DATABASE <name>

-- create a retention policy
CREATE RETENTION POLICY <rp-name> ON <db-name> DURATION <duration> REPLICATION <n> [DEFAULT]

-- alter retention policy
ALTER RETENTION POLICY <rp-name> ON <db-name> (DURATION <duration> | REPLICATION <n> | DEFAULT)+

-- drop a database
DROP DATABASE <name>
```

# Users and permissions

```sql
-- create user
CREATE USER <name> WITH PASSWORD <password>

-- grant privilege on a database
GRANT <privilege> ON <db> TO <user>

-- grant cluster admin privileges
GRANT ALL [PRIVILEGES] TO <user>

-- revoke privilege
REVOKE <privilege> ON <db> FROM <user>

-- revoke all privileges for a DB
REVOKE ALL [PRIVILEGES] ON <db> FROM <user>

-- revoke all of user's privileges (all DBs and/or cluster admin)
REVOKE ALL [PRIVILEGES] FROM <user>

-- delete a user
DROP USER <name>
```
<privilege> := READ | WRITE | All [PRIVILEGES]

# Select

```sql
-- get the top 10 host measurements for the last hour (same host can appear multiple times)
SELECT top(10, value), host FROM cpu WHERE time > now() - 1h

-- get the top 10 unique hosts for the last hour
SELECT top(10, value), distinct(host) FROM cpu WHERE time > now() - 1h
```

## Group By

# Delete

# Series

## Destroy

```sql
DROP MEASUREMENT <name>
DROP MEASUREMENT cpu WHERE region = 'uswest'
```

## List

List series queries are for pulling out individual series from measurement names and tag data. They're useful for discovery.

```sql
-- list measurement names
LIST MEASUREMENTS
LIST MEASUREMENTS WHERE service = 'redis'

-- list all series across all measurements/tagsets
LIST SERIES

-- get a list of all series for any measurements where tag key region = tak value 'uswest'
LIST SERIES WHERE region = 'uswest'

LIST SERIES FROM cpu_load WHERE region = 'uswest' LIMIT 10

-- get a list of all tag keys across all measurements
LIST TAG KEYS

-- list all the tag keys for a given measurement
LIST TAG KEYS FROM cpu
LIST TAG KEYS FROM temperature, wind_speed

-- list all the tag values. note that a single WHERE TAG KEY = '...' clause is required
LIST TAG VALUES WHERE TAG KEY = 'region'
LIST TAG VALUES FROM cpu WHERE region = 'uswest' and TAG KEY = 'host'

-- and you can do stuff against fields
LIST FIELD KEYS FROM cpu

-- but you can't do this
LIST FIELD VALUES
-- we don't index field values, so this query should be invalid.
```

Note that `FROM` and `WHERE` are optional clauses in all of the list series queries.

And the list series output looks like this:

```json
[
    {
        "name": "cpu",
        "columns": ["id", "region", "host"],
        "values": [
            1, "uswest", "servera",
            2, "uswest", "serverb"
        ]
    },
    {
        "name": "reponse_time",
        "columns": ["id", "application", "host"],
        "values": [
            3, "myRailsApp", "servera"
        ]
    }
]
```

# Continuous Queries

Continous queries are going to be inspired by MySQL `TRIGGER` syntax:

http://dev.mysql.com/doc/refman/5.0/en/trigger-syntax.html

Instead of having automatically-assigned ids, named continuous queries allows for some level of duplication prevention,
particularly in the case where creation is scripted.

## Create

    CREATE CONTINUOUS QUERY <name> AS SELECT ... FROM ...

## Destroy

    DROP CONTINUOUS QUERY <name>

## List

    LIST CONTINUOUS QUERIES