influxdb/influxql/INFLUXQL.md

# The Influx Query Language Specification

## Introduction

This is a reference for the Influx Query Language ("InfluxQL").

InfluxQL is a SQL-like query language for interacting with InfluxDB.  It has been lovingly crafted to feel familiar to those coming from other
SQL or SQL-like environments while providing features specific to storing
and analyzing time series data.

## Notation

This specification uses the same notation used by Google's Go programming language, which can be found at http://golang.org.  The syntax is specified in Extended Backus-Naur Form ("EBNF"):

```
Production  = production_name "=" [ Expression ] "." .
Expression  = Alternative { "|" Alternative } .
Alternative = Term { Term } .
Term        = production_name | token [ "…" token ] | Group | Option | Repetition .
Group       = "(" Expression ")" .
Option      = "[" Expression "]" .
Repetition  = "{" Expression "}" .
```

Notation operators in order of increasing precedence:

```
|   alternation
()  grouping
[]  option (0 or 1 times)
{}  repetition (0 to n times)
```

## Characters & Digits

```
newline             = /* the Unicode code point U+000A */ .
unicode_char        = /* an arbitrary Unicode code point except newline */ .
ascii_letter        = "A" .. "Z" | "a" .. "z" .
decimal_digit       = "0" .. "9" .
```

## Database name

Database names are more limited than other identifiers because they appear in URLs.

The rules:

- must start with an upper or lowercase ASCII letter
- may contain only ASCII leters, decimal digits, "_", and "-"

```
db_name             = ascii_letter { ascii_letter | decimal_digit | "_" | "-" } .
```

#### Examples:

```
mydb
MyDB
my-db_3
```

## Identifiers

Identifiers are things like measurement names, retention policy names, tag keys, etc.

The rules:

- double quoted identifiers can contain any unicode character other than a new
- double quoted identifiers can contain escaped `"` characters (i.e., `\"`)
- unquoted identifiers must start with an upper or lowercase ASCII character
- unquoted identifiers may contain only ASCII letters, decimal digits, "_", and "."

```
identifier          = unquoted_identifier | quoted_identifier .
unquoted_identifier = ascii_letter { ascii_letter | decimal_digit | "_" | "." } .
quoted_identifier   = `"` unicode_char { unicode_char } `"` .
```

#### Examples:

```
cpu
"1h.cpu"
"1_Crazy-1337.identifer>NAME"
```

## Keywords

```
ALL          ALTER        AS           ASC          BEGIN        BY
CREATE       CONTINUOUS   DATABASE     DATABASES    DEFAULT      DELETE
DESC         DROP         DURATION     END          EXISTS       EXPLAIN
FIELD        FROM         GRANT        GROUP        IF           IN
INNER        INSERT       INTO         KEY          KEYS         LIMIT
SHOW         MEASUREMENT  MEASUREMENTS OFFSET       ON           ORDER
PASSWORD     POLICY       POLICIES     PRIVILEGES   QUERIES      QUERY
READ         REPLICATION  RETENTION    REVOKE       SELECT       SERIES
TAG          TO           USER         USERS        VALUES       WHERE
WITH         WRITE
```

## Literals

### Numbers

InfluxQL supports decimal integer literals and float literals.  Hex, octal, etc. are not
currently supported.

```
int_lit             = decimal_lit .
decimal_lit         = ( "1" .. "9" ) { decimal_digit } .
float_lit           = decimals "." decimals .
```

### Strings

String literals must be surrounded by single quotes. Strings may contain `'` characters as long as they are escaped (i.e., `\'`).

```
string_lit          = `'` { unicode_char } `'`' .
```

### Durations

Duration literals specify a length of time and are specified by an integer
followed by (without spaces) the duration units.

| Units  | Meaning                                 |
|--------|-----------------------------------------|
| u or µ | microseconds (1 millionth of a second)  |
| ms     | milliseconds (1 thousandth of a second) |
| s      | second                                  |
| m      | minute                                  |
| h      | hour                                    |
| d      | day                                     |
| w      | week                                    |


```
duration_lit        = decimals duration_unit .
duration_unit       = "u" | "µ" | "s" | "h" | "d" | "w" | "ms" .
```

### Dates & Times

The date & time literal format is not specified in EBNF like the rest of this
document.  It is specified using Go's date / time parsing format, which is
a reference date written in the format required by InfluxQL.  The reference
date time is:

January 2nd, 2006 at 3:04:05 PM

```
time_lit            = "2006-01-02 15:04:05.999999" | "2006-01-02"
```

### Boolean

```
bool_lit            = TRUE | FALSE .
```

## Queries

A query is composed of one or more statements separated by a semicolon.

```
query               = statement { ; statement } .

statement           = alter_retention_policy_stmt |
                      create_continuous_query_stmt |
                      create_database_stmt |
                      create_retention_policy_stmt |
                      create_user_stmt |
                      delete_stmt |
                      drop_continuous_query_stmt |
                      drop_database_stmt |
                      drop_measurement_stmt |
                      drop_retention_policy_stmt |
                      drop_series_stmt |
                      drop_user_stmt |
                      grant_stmt |
                      show_continuous_queries_stmt |
                      show_databases_stmt |
                      show_field_keys_stmt |
                      show_measurements_stmt |
                      show_retention_policies |
                      show_series_stmt |
                      show_tag_keys_stmt |
                      show_tag_values_stmt |
                      show_users_stmt |
                      revoke_stmt |
                      select_stmt .
```

## Statements

### ALTER RETENTION POLICY

```
alter_retention_policy_stmt  = "ALTER RETENTION POLICY" policy_name "ON"
                               db_name retention_policy_option
                               [ retention_policy_option ]
                               [ retention_policy_option ] .

policy_name                  = identifier .

retention_policy_option      = retention_policy_duration |
                               retention_policy_replication |
                               "DEFAULT" .

retention_policy_duration    = "DURATION" duration_lit .
retention_policy_replication = "REPLICATION" int_lit
```

#### Examples:

```sql
-- Set default retention policy for mydb to 1h.cpu.
ALTER RETENTION POLICY "1h.cpu" ON mydb DEFAULT;

-- Change duration and replication factor.
ALTER RETENTION POLICY policy1 ON somedb DURATION 1h REPLICATION 4
```

### CREATE CONTINUOUS QUERY

```
create_continuous_query_stmt = "CREATE CONTINUOUS QUERY" query_name "ON" db_name
                               "BEGIN" select_stmt "END" .

query_name                   = identifier .
```

#### Examples:

```sql
CREATE CONTINUOUS QUERY 10m_event_count
ON db_name
BEGIN
  SELECT count(value)
  INTO 10m.events
  FROM events
  GROUP BY time(10m)
END;

-- this selects from the output of one continuous query and outputs to another series
CREATE CONTINUOUS QUERY 1h_event_count
ON db_name
BEGIN
  SELECT sum(count) as count
  INTO 1h.events
  FROM events
  GROUP BY time(1h)
END;
```

### CREATE DATABASE

```
create_database_stmt = "CREATE DATABASE" db_name
```

#### Example:

```sql
CREATE DATABASE foo
```

### CREATE RETENTION POLICY

```
create_retention_policy_stmt = "CREATE RETENTION POLICY" policy_name "ON"
                               db_name retention_policy_duration
                               retention_policy_replication
                               [ "DEFAULT" ] .
```

#### Examples

```sql
-- Create a retention policy.
CREATE RETENTION POLICY "10m.events" ON somedb DURATION 10m REPLICATION 2;

-- Create a retention policy and set it as the default.
CREATE RETENTION POLICY "10m.events" ON somedb DURATION 10m REPLICATION 2 DEFAULT;
```

### CREATE USER

```
create_user_stmt = "CREATE USER" user_name "WITH PASSWORD" password
                   [ "WITH ALL PRIVILEGES" ] .
```

#### Examples:

```sql
-- Create a normal database user.
CREATE USER jdoe WITH PASSWORD "1337password";

-- Create a cluster admin.
-- Note: Unlike the GRANT statement, the "PRIVILEGES" keyword is required here.
CREATE USER jdoe WITH PASSWORD "1337password" WITH ALL PRIVILEGES;
```

### DELETE

```
delete_stmt  = "DELETE" from_clause where_clause .
```

#### Example:

```sql
-- delete data points from the cpu measurement where the region tag
-- equals 'uswest'
DELETE FROM cpu WHERE region = 'uswest';
```

### DROP CONTINUOUS QUERY

drop_continuous_query_stmt = "DROP CONTINUOUS QUERY" query_name .

#### Example:

```sql
DROP CONTINUOUS QUERY myquery;
```

### DROP DATABASE

drop_database_stmt = "DROP DATABASE" db_name .

#### Example:

```sql
DROP DATABASE mydb;
```

### DROP MEASUREMENT

```
drop_measurement_stmt = "DROP MEASUREMENT" measurement .
```

#### Examples:

```sql
-- drop the cpu measurement
DROP MEASUREMENT cpu;
```

### DROP RETENTION POLICY

```
drop_retention_policy_stmt = "DROP RETENTION POLICY" policy_name "ON" db_name .
```

#### Example:

```sql
-- drop the retention policy named 1h.cpu from mydb
DROP RETENTION POLICY "1h.cpu" ON mydb;
```

### DROP SERIES

```
drop_series_stmt = "DROP SERIES" [ from_clause ] [ where_clause ]
```

#### Example:

```sql

```

### DROP USER

```
drop_user_stmt = "DROP USER" user_name .
```

#### Example:

```sql
DROP USER jdoe;

```

### GRANT

NOTE: Users can be granted privileges on databases that do not exist.

```
grant_stmt = "GRANT" privilege [ on_clause ] to_clause
```

#### Examples:

```sql
-- grant cluster admin privileges
GRANT ALL TO jdoe;

-- grant read access to a database
GRANT READ ON mydb TO jdoe;
```

### SHOW CONTINUOUS QUERIES

show_continuous_queries_stmt = "SHOW CONTINUOUS QUERIES"

#### Example:

```sql
-- show all continuous queries
SHOW CONTINUOUS QUERIES;
```

### SHOW DATABASES

```
show_databases_stmt = "SHOW DATABASES" .
```

#### Example:

```sql
-- show all databases
SHOW DATABASES;
```

### SHOW FIELD

show_field_keys_stmt =

#### Examples:

```sql

```

### SHOW MEASUREMENTS

show_measurements_stmt = [ where_clause ] [ group_by_clause ] [ limit_clause ]
                         [ offset_clause ] .

```sql
-- show all measurements
SHOW MEASUREMENTS;

-- show measurements where region tag = 'uswest' AND host tag = 'serverA'
SHOW MEASUREMENTS WHERE region = 'uswest' AND host = 'serverA';
```

### SHOW RETENTION POLICIES

```
show_retention_policies = "SHOW RETENTION POLICIES" db_name .
```

#### Example:

```sql
-- show all retention policies on a database
SHOW RETENTION POLICIES mydb;
```

### SHOW SERIES

```
show_series_stmt = [ from_clause ] [ where_clause ] [ group_by_clause ]
                   [ limit_clause ] [ offset_clause ] .
```

#### Example:

```sql

```

### SHOW TAG KEYS

```
show_tag_keys_stmt = [ from_clause ] [ where_clause ] [ group_by_clause ]
                     [ limit_clause ] [ offset_clause ] .
```

#### Examples:

```sql
-- show all tag keys
SHOW TAG KEYS;

-- show all tag keys from the cpu measurement
SHOW TAG KEYS FROM cpu;

-- show all tag keys from the cpu measurement where the region key = 'uswest'
SHOW TAG KEYS FROM cpu WHERE region = 'uswest';

-- show sll tag keys where the host key = 'serverA'
SHOW TAG KEYS WHERE host = 'serverA';
```

### SHOW TAG VALUES

```
show_tag_values_stmt = [ from_clause ] with_tag_clause [ where_clause ]
                       [ group_by_clause ] [ limit_clause ] [ offset_clause ] .
```

#### Examples:

```sql
-- show all tag values across all measurements for the region tag
SHOW TAG VALUES WITH TAG = 'region';

-- show tag values from the cpu measurement for the region tag
SHOW TAG VALUES FROM cpu WITH TAG = 'region';

-- show tag values from the cpu measurement for region & host tag keys where service = 'redis'
SHOW TAG VALUES FROM cpu WITH TAG IN (region, host) WHERE service = 'redis';
```

### SHOW USERS

```
show_users_stmt = "SHOW USERS" .
```

#### Example:

```sql
-- show all users
SHOW USERS;
```

### REVOKE

```
revoke_stmt = privilege [ "ON" db_name ] "FROM" user_name
```

#### Examples:

```sql
-- revoke cluster admin from jdoe
REVOKE ALL PRIVILEGES FROM jdoe;

-- revoke read privileges from jdoe on mydb
REVOKE READ ON mydb FROM jdoe;
```

### SELECT

```
select_stmt = fields from_clause [ into_clause ] [ where_clause ]
              [ group_by_clause ] [ order_by_clause ] [ limit_clause ]
              [ offset_clause ] .
```

#### Examples:

```sql
-- select mean value from the cpu measurement where region = 'uswest' grouped by 10 minute intervals
SELECT mean(value) FROM cpu WHERE region = 'uswest' GROUP BY time(10m);
```

## Clauses

```
from_clause     = "FROM" measurements .

group_by_clause = "GROUP BY" dimensions .

limit_clause    = "LIMIT" int_lit .

offset_clause   = "OFFSET" int_lit .

on_clause       = db_name .

order_by_clause = "ORDER BY" sort_fields .

to_clause       = user_name .

where_clause    = "WHERE" expr .
```

## Expressions

```
binary_op        = "+" | "-" | "*" | "/" | "AND" | "OR" | "=" | "!=" | "<" |
                   "<=" | ">" | ">=" .

expr             = unary_expr { binary_op unary_expr } .

unary_expr       = "(" expr ")" | var_ref | time_lit | string_lit |
                   number_lit | bool_lit | duration_lit .

## Other

decimals          = decimal_digit { decimal_digit } .

dimenson         = expr .

dimensons        = dimenson { "," dimenson } .

field            = expr [ alias ] .

fields           = field { "," field } .

measurement      = measurement_name |
                   ( policy_name "." measurement_name ) |
                   ( db_name "." [ policy_name ] "." measurement_name ) .

measurements     = measurement { "," measurement } .

measurement_name = identifier .

password         = identifier .

policy_name      = identifier .

privilege        = "ALL" [ "PRIVILEGES" ] | "READ" | "WRITE" .

series_id        = int_lit .

sort_field       = field_name [ ASC | DESC ] .

sort_fields      = sort_field { "," sort_field } .

user_name        = identifier .
```