Schema exploration using InfluxQL

InfluxQL is an SQL-like query language for interacting with data in InfluxDB.The following sections cover useful query syntax for exploring your schema.

SHOW DATABASESSHOW RETENTION POLICIESSHOW SERIES
SHOW MEASUREMENTSSHOW TAG KEYSSHOW TAG VALUES
SHOW FIELD KEYSFilter meta queries by time

Sample data

The data used in this document are available for download on the Sample Data page.

Before proceeding, login to the Influx CLI.

  1. $ influx -precision rfc3339
  2. Connected to http://localhost:8086 version 1.4.x
  3. InfluxDB shell 1.4.x
  4. >

SHOW DATABASES

Returns a list of all databases on your instance.

Syntax

  1. SHOW DATABASES

Examples

Run a SHOW DATABASES query

  1. > SHOW DATABASES
  3. name: databases
  4. name
  5. ----
  6. NOAA_water_database
  7. _internal

The query returns database names in a tabular format.This InfluxDB instance has two databases: NOAA_water_database and _internal.

SHOW RETENTION POLICIES

Returns a list of retention policies for the specified database.

Syntax

  1. SHOW RETENTION POLICIES [ON <database_name>]

Description of syntax

ON <database_name> is optional.If the query does not include ON <database_name>, you must specify thedatabase with USE <database_name> in the CLI or with the db querystring parameter in the InfluxDB API request.

Examples

Run a SHOW RETENTION POLICIES query with the ON clause

  1. > SHOW RETENTION POLICIES ON NOAA_water_database
  3. name      duration   shardGroupDuration   replicaN   default
  4. ----      --------   ------------------   --------   -------
  5. autogen   0s         168h0m0s             1          true

The query returns the list of retention policies in the NOAA_water_databasedatabase in tabular format.The database has one retention policy called autogen.The autogen retention policy has an infinite duration,a seven-day shard group duration,a replication factorof one, and it is the DEFAULT retention policy for the database.

Run a SHOW RETENTION POLICIES query without the ON clause

CLIInfluxDB API

Specify the database with USE <database_name>

  1. > USE NOAA_water_database
  2. Using database NOAA_water_database
  4. > SHOW RETENTION POLICIES
  6. name      duration   shardGroupDuration   replicaN   default
  7. ----      --------   ------------------   --------   -------
  8. autogen   0s         168h0m0s             1          true

Specify the database with the db query string parameter:

  1. ~# curl -G "http://localhost:8086/query?db=NOAA_water_database&pretty=true" --data-urlencode "q=SHOW RETENTION POLICIES"
  3. {
  4.     "results": [
  5.         {
  6.             "statement_id": 0,
  7.             "series": [
  8.                 {
  9.                     "columns": [
  10.                         "name",
  11.                         "duration",
  12.                         "shardGroupDuration",
  13.                         "replicaN",
  14.                         "default"
  15.                     ],
  16.                     "values": [
  17.                         [
  18.                             "autogen",
  19.                             "0s",
  20.                             "168h0m0s",
  21.                             1,
  22.                             true
  23.                         ]
  24.                     ]
  25.                 }
  26.             ]
  27.         }
  28.     ]
  29. }

SHOW SERIES

Returns a list of series forthe specified database.

Syntax

  1. SHOW SERIES [ON <database_name>] [FROM_clause] [WHERE <tag_key> <operator> [ '<tag_value>' | <regular_expression>]] [LIMIT_clause] [OFFSET_clause]

Description of syntax

ON <database_name> is optional.If the query does not include ON <database_name>, you must specify thedatabase with USE <database_name> in the CLI or with the db querystring parameter in the InfluxDB API request.

The FROM, WHERE, LIMIT, and OFFSET clauses are optional.The WHERE clause supports tag comparisons; field comparisons are notvalid for the SHOW SERIES query.

Supported operators in the WHERE clause:=   equal to<> not equal to!= not equal to=~ matches against!~ doesn’t match against

See the Data Exploration page for documentation on theFROM clause,LIMIT clause,OFFSET clause,and on Regular Expressions in Queries.

Examples

Run a SHOW SERIES query with the ON clause

  1. // Returns series for all shards in the database
  2. > SHOW SERIES ON NOAA_water_database
  4. key
  5. ---
  6. average_temperature,location=coyote_creek
  7. average_temperature,location=santa_monica
  8. h2o_feet,location=coyote_creek
  9. h2o_feet,location=santa_monica
  10. h2o_pH,location=coyote_creek
  11. h2o_pH,location=santa_monica
  12. h2o_quality,location=coyote_creek,randtag=1
  13. h2o_quality,location=coyote_creek,randtag=2
  14. h2o_quality,location=coyote_creek,randtag=3
  15. h2o_quality,location=santa_monica,randtag=1
  16. h2o_quality,location=santa_monica,randtag=2
  17. h2o_quality,location=santa_monica,randtag=3
  18. h2o_temperature,location=coyote_creek
  19. h2o_temperature,location=santa_monica

The query’s output is similar to the line protocol format.Everything before the first comma is the measurement name.Everything after the first comma is either a tag key or a tag value.The NOAA_water_database has five different measurements and 14 different series.

Run a SHOW SERIES query without the ON clause

CLIInfluxDB API

Specify the database with USE <database_name>

  1. > USE NOAA_water_database
  2. Using database NOAA_water_database
  4. > SHOW SERIES
  6. key
  7. ---
  8. average_temperature,location=coyote_creek
  9. average_temperature,location=santa_monica
  10. h2o_feet,location=coyote_creek
  11. h2o_feet,location=santa_monica
  12. h2o_pH,location=coyote_creek
  13. h2o_pH,location=santa_monica
  14. h2o_quality,location=coyote_creek,randtag=1
  15. h2o_quality,location=coyote_creek,randtag=2
  16. h2o_quality,location=coyote_creek,randtag=3
  17. h2o_quality,location=santa_monica,randtag=1
  18. h2o_quality,location=santa_monica,randtag=2
  19. h2o_quality,location=santa_monica,randtag=3
  20. h2o_temperature,location=coyote_creek
  21. h2o_temperature,location=santa_monica

Specify the database with the db query string parameter:

  1. ~# curl -G "http://localhost:8086/query?db=NOAA_water_database&pretty=true" --data-urlencode "q=SHOW SERIES"
  3. {
  4.     "results": [
  5.         {
  6.             "statement_id": 0,
  7.             "series": [
  8.                 {
  9.                     "columns": [
  10.                         "key"
  11.                     ],
  12.                     "values": [
  13.                         [
  14.                             "average_temperature,location=coyote_creek"
  15.                         ],
  16.                         [
  17.                             "average_temperature,location=santa_monica"
  18.                         ],
  19.                         [
  20.                             "h2o_feet,location=coyote_creek"
  21.                         ],
  22.                         [
  23.                             "h2o_feet,location=santa_monica"
  24.                         ],
  25.                         [
  26.                             "h2o_pH,location=coyote_creek"
  27.                         ],
  28.                         [
  29.                             "h2o_pH,location=santa_monica"
  30.                         ],
  31.                         [
  32.                             "h2o_quality,location=coyote_creek,randtag=1"
  33.                         ],
  34.                         [
  35.                             "h2o_quality,location=coyote_creek,randtag=2"
  36.                         ],
  37.                         [
  38.                             "h2o_quality,location=coyote_creek,randtag=3"
  39.                         ],
  40.                         [
  41.                             "h2o_quality,location=santa_monica,randtag=1"
  42.                         ],
  43.                         [
  44.                             "h2o_quality,location=santa_monica,randtag=2"
  45.                         ],
  46.                         [
  47.                             "h2o_quality,location=santa_monica,randtag=3"
  48.                         ],
  49.                         [
  50.                             "h2o_temperature,location=coyote_creek"
  51.                         ],
  52.                         [
  53.                             "h2o_temperature,location=santa_monica"
  54.                         ]
  55.                     ]
  56.                 }
  57.             ]
  58.         }
  59.     ]
  60. }

Run a SHOW SERIES query with several clauses

  1. > SHOW SERIES ON NOAA_water_database FROM "h2o_quality" WHERE "location" = 'coyote_creek' LIMIT 2
  3. key
  4. ---
  5. h2o_quality,location=coyote_creek,randtag=1
  6. h2o_quality,location=coyote_creek,randtag=2

The query returns all series in the NOAA_water_database database that areassociated with the h2o_quality measurement and the tag location = coyote_creek.The LIMIT clause limits the number of series returned to two.

Run a SHOW SERIES query limited by time

Limit series returned within a specified shard group duration.

  1. // Returns all series in the current shard.
  2. > SHOW SERIES ON NOAA_water_database WHERE time < now() - 1m
  4. key
  5. ---
  6. average_temperature,location=coyote_creek
  7. h2o_feet,location=coyote_creek
  8. h2o_pH,location=coyote_creek
  9. h2o_quality,location=coyote_creek,randtag=1
  10. h2o_quality,location=coyote_creek,randtag=2
  11. h2o_quality,location=coyote_creek,randtag=3
  12. h2o_temperature,location=coyote_creek

The query above returns all series in the NOAA_water_database database in the current shard group. The WHERE clause limits results to series in the shard group that contain a timestamp in the last minute. Note, if a shard group duration is 7 days, results returned may be up to 7 days old.

  1. // Returns all series in shard groups that contain a timestamp in the last 28 days.
  2. > SHOW SERIES ON NOAA_water_database WHERE time < now() - 28d
  4. key
  5. ---
  6. average_temperature,location=coyote_creek
  7. average_temperature,location=santa_monica
  8. h2o_feet,location=coyote_creek
  9. h2o_feet,location=santa_monica
  10. h2o_pH,location=coyote_creek
  11. h2o_pH,location=santa_monica
  12. h2o_quality,location=coyote_creek,randtag=1
  13. h2o_quality,location=coyote_creek,randtag=2
  14. h2o_quality,location=coyote_creek,randtag=3
  15. h2o_quality,location=santa_monica,randtag=1
  16. h2o_quality,location=santa_monica,randtag=2
  17. h2o_quality,location=santa_monica,randtag=3
  18. h2o_temperature,location=coyote_creek
  19. h2o_temperature,location=santa_monica

Note, if the specified shard group duration is 7 days, the query above returns series for the last 3 or 4 shards.

SHOW MEASUREMENTS

Returns a list of measurementsfor the specified database.

Syntax

  1. SHOW MEASUREMENTS [ON <database_name>] [WITH MEASUREMENT <operator> ['<measurement_name>' | <regular_expression>]] [WHERE <tag_key> <operator> ['<tag_value>' | <regular_expression>]] [LIMIT_clause] [OFFSET_clause]

Description of Syntax

ON <database_name> is optional.If the query does not include ON <database_name>, you must specify thedatabase with USE <database_name> in the CLI or with the db querystring parameter in the InfluxDB API request.

The WITH, WHERE, LIMIT and OFFSET clauses are optional.The WHERE clause supports tag comparisons; field comparisons are not valid for the SHOW MEASUREMENTS query.

Supported operators in the WHERE clause:=   equal to<> not equal to!= not equal to=~ matches against!~ doesn’t match against

See the Data Exploration page for documentation on theLIMIT clause,OFFSET clause,and on Regular expressions in queries.

Examples

Run a SHOW MEASUREMENTS query with the ON clause

  1. > SHOW MEASUREMENTS ON NOAA_water_database
  3. name: measurements
  4. name
  5. ----
  6. average_temperature
  7. h2o_feet
  8. h2o_pH
  9. h2o_quality
  10. h2o_temperature

The query returns the list of measurements in the NOAA_water_databasedatabase.The database has five measurements: average_temperature, h2o_feet,h2o_pH, h2o_quality, and h2o_temperature.

Run a SHOW MEASUREMENTS query without the ON clause

CLIInfluxDB API

Specify the database with USE <database_name>

  1. > USE NOAA_water_database
  2. Using database NOAA_water_database
  4. > SHOW MEASUREMENTS
  5. name: measurements
  6. name
  7. ----
  8. average_temperature
  9. h2o_feet
  10. h2o_pH
  11. h2o_quality
  12. h2o_temperature

Specify the database with the db query string parameter:

  1. ~# curl -G "http://localhost:8086/query?db=NOAA_water_database&pretty=true" --data-urlencode "q=SHOW MEASUREMENTS"
  3. {
  4.   {
  5.       "results": [
  6.           {
  7.               "statement_id": 0,
  8.               "series": [
  9.                   {
  10.                       "name": "measurements",
  11.                       "columns": [
  12.                           "name"
  13.                       ],
  14.                       "values": [
  15.                           [
  16.                               "average_temperature"
  17.                           ],
  18.                           [
  19.                               "h2o_feet"
  20.                           ],
  21.                           [
  22.                               "h2o_pH"
  23.                           ],
  24.                           [
  25.                               "h2o_quality"
  26.                           ],
  27.                           [
  28.                               "h2o_temperature"
  29.                           ]
  30.                       ]
  31.                   }
  32.               ]
  33.           }
  34.       ]
  35.   }

Run a SHOW MEASUREMENTS query with several clauses (i)

  1. > SHOW MEASUREMENTS ON NOAA_water_database WITH MEASUREMENT =~ /h2o.*/ LIMIT 2 OFFSET 1
  3. name: measurements
  4. name
  5. ----
  6. h2o_pH
  7. h2o_quality

The query returns the measurements in the NOAA_water_database database thatstart with h2o.The LIMIT and OFFSET clauses limit the number of measurement names returned totwo and offset the results by one, skipping the h2o_feet measurement.

Run a SHOW MEASUREMENTS query with several clauses (ii)

  1. > SHOW MEASUREMENTS ON NOAA_water_database WITH MEASUREMENT =~ /h2o.*/ WHERE "randtag"  =~ /\d/
  3. name: measurements
  4. name
  5. ----
  6. h2o_quality

The query returns all measurements in the NOAA_water_database that startwith h2o and have values for the tag key randtag that include an integer.

SHOW TAG KEYS

Returns a list of tag keysassociated with the specified database.

Syntax

  1. SHOW TAG KEYS [ON <database_name>] [FROM_clause] [WHERE <tag_key> <operator> ['<tag_value>' | <regular_expression>]] [LIMIT_clause] [OFFSET_clause]

Description of syntax

ON <database_name> is optional.If the query does not include ON <database_name>, you must specify thedatabase with USE <database_name> in the CLI or with the db querystring parameter in the InfluxDB API request.

The FROM clause and the WHERE clause are optional.The WHERE clause supports tag comparisons; field comparisons are notvalid for the SHOW TAG KEYS query.

Supported operators in the WHERE clause:=   equal to<> not equal to!= not equal to=~ matches against!~ doesn’t match against

See the Data Exploration page for documentation on theFROM clause,LIMIT clause,OFFSET clause,and on Regular Expressions in Queries.

Examples

Run a SHOW TAG KEYS query with the ON clause

  1. > SHOW TAG KEYS ON "NOAA_water_database"
  3. name: average_temperature
  4. tagKey
  5. ------
  6. location
  8. name: h2o_feet
  9. tagKey
  10. ------
  11. location
  13. name: h2o_pH
  14. tagKey
  15. ------
  16. location
  18. name: h2o_quality
  19. tagKey
  20. ------
  21. location
  22. randtag
  24. name: h2o_temperature
  25. tagKey
  26. ------
  27. location

The query returns the list of tag keys in the NOAA_water_database database.The output groups tag keys by measurement name;it shows that every measurement has the location tag key and that theh2o_quality measurement has an additional randtag tag key.

Run a SHOW TAG KEYS query without the ON clause

CLIInfluxDB API

Specify the database with USE <database_name>

  1. > USE NOAA_water_database
  2. Using database NOAA_water_database
  4. > SHOW TAG KEYS
  6. name: average_temperature
  7. tagKey
  8. ------
  9. location
  11. name: h2o_feet
  12. tagKey
  13. ------
  14. location
  16. name: h2o_pH
  17. tagKey
  18. ------
  19. location
  21. name: h2o_quality
  22. tagKey
  23. ------
  24. location
  25. randtag
  27. name: h2o_temperature
  28. tagKey
  29. ------
  30. location

Specify the database with the db query string parameter:

  1. ~# curl -G "http://localhost:8086/query?db=NOAA_water_database&pretty=true" --data-urlencode "q=SHOW TAG KEYS"
  3. {
  4.     "results": [
  5.         {
  6.             "statement_id": 0,
  7.             "series": [
  8.                 {
  9.                     "name": "average_temperature",
  10.                     "columns": [
  11.                         "tagKey"
  12.                     ],
  13.                     "values": [
  14.                         [
  15.                             "location"
  16.                         ]
  17.                     ]
  18.                 },
  19.                 {
  20.                     "name": "h2o_feet",
  21.                     "columns": [
  22.                         "tagKey"
  23.                     ],
  24.                     "values": [
  25.                         [
  26.                             "location"
  27.                         ]
  28.                     ]
  29.                 },
  30.                 {
  31.                     "name": "h2o_pH",
  32.                     "columns": [
  33.                         "tagKey"
  34.                     ],
  35.                     "values": [
  36.                         [
  37.                             "location"
  38.                         ]
  39.                     ]
  40.                 },
  41.                 {
  42.                     "name": "h2o_quality",
  43.                     "columns": [
  44.                         "tagKey"
  45.                     ],
  46.                     "values": [
  47.                         [
  48.                             "location"
  49.                         ],
  50.                         [
  51.                             "randtag"
  52.                         ]
  53.                     ]
  54.                 },
  55.                 {
  56.                     "name": "h2o_temperature",
  57.                     "columns": [
  58.                         "tagKey"
  59.                     ],
  60.                     "values": [
  61.                         [
  62.                             "location"
  63.                         ]
  64.                     ]
  65.                 }
  66.             ]
  67.         }
  68.     ]
  69. }

Run a SHOW TAG KEYS query with several clauses

  1. > SHOW TAG KEYS ON "NOAA_water_database" FROM "h2o_quality" LIMIT 1 OFFSET 1
  3. name: h2o_quality
  4. tagKey
  5. ------
  6. randtag

The query returns tag keys from the h2o_quality measurement in theNOAA_water_database database.The LIMIT and OFFSET clauses limit the number of tag keys returned to oneand offsets the results by one.

SHOW TAG VALUES

Returns the list of tag valuesfor the specified tag key(s) in the database.

Syntax

  1. SHOW TAG VALUES [ON <database_name>][FROM_clause] WITH KEY [ [<operator> "<tag_key>" | <regular_expression>] | [IN ("<tag_key1>","<tag_key2")]] [WHERE <tag_key> <operator> ['<tag_value>' | <regular_expression>]] [LIMIT_clause] [OFFSET_clause]

Description of syntax

ON <database_name> is optional.If the query does not include ON <database_name>, you must specify thedatabase with USE <database_name> in the CLI or with the db query string parameter in the InfluxDB API request.

The WITH clause is required.It supports specifying a single tag key, a regular expression, and multiple tag keys.

The FROM, WHERE, LIMIT, and OFFSET clauses are optional.The WHERE clause supports tag comparisons; field comparisons are notvalid for the SHOW TAG KEYS query.

Supported operators in the WITH and WHERE clauses:=   equal to<> not equal to!= not equal to=~ matches against!~ doesn’t match against

See the Data Exploration page for documentation on theFROM clause,LIMIT clause,OFFSET clause,and on Regular Expressions in Queries.

Examples

Run a SHOW TAG VALUES query with the ON clause

  1. > SHOW TAG VALUES ON "NOAA_water_database" WITH KEY = "randtag"
  3. name: h2o_quality
  4. key       value
  5. ---       -----
  6. randtag   1
  7. randtag   2
  8. randtag   3

The query returns all tag values of the randtag tag key in the NOAA_water_databasedatabase.SHOW TAG VALUES groups query results by measurement name.

Run a SHOW TAG VALUES query without the ON clause

CLIInfluxDB API

Specify the database with USE <database_name>

  1. > USE NOAA_water_database
  2. Using database NOAA_water_database
  4. > SHOW TAG VALUES WITH KEY = "randtag"
  6. name: h2o_quality
  7. key       value
  8. ---       -----
  9. randtag   1
  10. randtag   2
  11. randtag   3

Specify the database with the db query string parameter:

  1. ~# curl -G "http://localhost:8086/query?db=NOAA_water_database&pretty=true" --data-urlencode 'q=SHOW TAG VALUES WITH KEY = "randtag"'
  3. {
  4.     "results": [
  5.         {
  6.             "statement_id": 0,
  7.             "series": [
  8.                 {
  9.                     "name": "h2o_quality",
  10.                     "columns": [
  11.                         "key",
  12.                         "value"
  13.                     ],
  14.                     "values": [
  15.                         [
  16.                             "randtag",
  17.                             "1"
  18.                         ],
  19.                         [
  20.                             "randtag",
  21.                             "2"
  22.                         ],
  23.                         [
  24.                             "randtag",
  25.                             "3"
  26.                         ]
  27.                     ]
  28.                 }
  29.             ]
  30.         }
  31.     ]
  32. }

Run a SHOW TAG VALUES query with several clauses

  1. > SHOW TAG VALUES ON "NOAA_water_database" WITH KEY IN ("location","randtag") WHERE "randtag" =~ /./ LIMIT 3
  3. name: h2o_quality
  4. key        value
  5. ---        -----
  6. location   coyote_creek
  7. location   santa_monica
  8. randtag       1

The query returns the tag values of the tag keys location and randtag forall measurements in the NOAA_water_database database where randtag has tag values.The LIMIT clause limits the number of tag values returned to three.

SHOW FIELD KEYS

Returns the field keys and thedata type of theirfield values.

Syntax

  1. SHOW FIELD KEYS [ON <database_name>] [FROM <measurement_name>]

Description of syntax

ON <database_name> is optional.If the query does not include ON <database_name>, you must specify thedatabase with USE <database_name> in the CLI or with the db querystring parameter in the InfluxDB API request.

The FROM clause is also optional.See the Data Exploration page for documentation on theFROM clause.

Note: A field’s data type can differ acrossshards.If your field has more than one type, SHOW FIELD KEYS returns the type thatoccurs first in the following list: float, integer, string, boolean.

Examples

Run a SHOW FIELD KEYS query with the ON clause

  1. > SHOW FIELD KEYS ON "NOAA_water_database"
  3. name: average_temperature
  4. fieldKey            fieldType
  5. --------            ---------
  6. degrees             float
  8. name: h2o_feet
  9. fieldKey            fieldType
  10. --------            ---------
  11. level description   string
  12. water_level         float
  14. name: h2o_pH
  15. fieldKey            fieldType
  16. --------            ---------
  17. pH                  float
  19. name: h2o_quality
  20. fieldKey            fieldType
  21. --------            ---------
  22. index               float
  24. name: h2o_temperature
  25. fieldKey            fieldType
  26. --------            ---------
  27. degrees             float

The query returns the field keys and field value data types for eachmeasurement in the NOAA_water_database database.

Run a SHOW FIELD KEYS query without the ON clause

CLIInfluxDB API

Specify the database with USE <database_name>

  1. > USE NOAA_water_database
  2. Using database NOAA_water_database
  4. > SHOW FIELD KEYS
  6. name: average_temperature
  7. fieldKey            fieldType
  8. --------            ---------
  9. degrees             float
  11. name: h2o_feet
  12. fieldKey            fieldType
  13. --------            ---------
  14. level description   string
  15. water_level         float
  17. name: h2o_pH
  18. fieldKey            fieldType
  19. --------            ---------
  20. pH                  float
  22. name: h2o_quality
  23. fieldKey            fieldType
  24. --------            ---------
  25. index               float
  27. name: h2o_temperature
  28. fieldKey            fieldType
  29. --------            ---------
  30. degrees             float

Specify the database with the db query string parameter:

  1. ~# curl -G "http://localhost:8086/query?db=NOAA_water_database&pretty=true" --data-urlencode 'q=SHOW FIELD KEYS'
  3. {
  4.     "results": [
  5.         {
  6.             "statement_id": 0,
  7.             "series": [
  8.                 {
  9.                     "name": "average_temperature",
  10.                     "columns": [
  11.                         "fieldKey",
  12.                         "fieldType"
  13.                     ],
  14.                     "values": [
  15.                         [
  16.                             "degrees",
  17.                             "float"
  18.                         ]
  19.                     ]
  20.                 },
  21.                 {
  22.                     "name": "h2o_feet",
  23.                     "columns": [
  24.                         "fieldKey",
  25.                         "fieldType"
  26.                     ],
  27.                     "values": [
  28.                         [
  29.                             "level description",
  30.                             "string"
  31.                         ],
  32.                         [
  33.                             "water_level",
  34.                             "float"
  35.                         ]
  36.                     ]
  37.                 },
  38.                 {
  39.                     "name": "h2o_pH",
  40.                     "columns": [
  41.                         "fieldKey",
  42.                         "fieldType"
  43.                     ],
  44.                     "values": [
  45.                         [
  46.                             "pH",
  47.                             "float"
  48.                         ]
  49.                     ]
  50.                 },
  51.                 {
  52.                     "name": "h2o_quality",
  53.                     "columns": [
  54.                         "fieldKey",
  55.                         "fieldType"
  56.                     ],
  57.                     "values": [
  58.                         [
  59.                             "index",
  60.                             "float"
  61.                         ]
  62.                     ]
  63.                 },
  64.                 {
  65.                     "name": "h2o_temperature",
  66.                     "columns": [
  67.                         "fieldKey",
  68.                         "fieldType"
  69.                     ],
  70.                     "values": [
  71.                         [
  72.                             "degrees",
  73.                             "float"
  74.                         ]
  75.                     ]
  76.                 }
  77.             ]
  78.         }
  79.     ]
  80. }

Run a SHOW FIELD KEYS query with the FROM clause

  1. > SHOW FIELD KEYS ON "NOAA_water_database" FROM "h2o_feet"
  3. name: h2o_feet
  4. fieldKey            fieldType
  5. --------            ---------
  6. level description   string
  7. water_level         float

The query returns the fields keys and field value data types for the h2o_feetmeasurement in the NOAA_water_database database.

Common Issues with SHOW FIELD KEYS

SHOW FIELD KEYS and field type discrepancies

Field valuedata typescannot differ within a shard but theycan differ across shards.SHOW FIELD KEYS returns every data type, across every shard, associated withthe field key.

Example

The all_the_types field stores four different data types:

  1. > SHOW FIELD KEYS
  3. name: mymeas
  4. fieldKey        fieldType
  5. --------        ---------
  6. all_the_types   integer
  7. all_the_types   float
  8. all_the_types   string
  9. all_the_types   boolean

Note that SHOW FIELD KEYS handles field type discrepancies differently fromSELECT statements.For more information, see theHow does InfluxDB handle field type discrepancies across shards?.

Filter meta queries by time

When you filter meta queries by time, you may see results outside of your specified time. Meta query results are filtered at the shard level, so results can be approximately as granular as your shard group duration. If your time filter spans multiple shards, you’ll get results from all shards with points in the specified time range. To review your shards and timestamps on points in the shard, run SHOW SHARDS. To learn more about shards and their duration, see recommended shard groups durations.

The example below shows how to filter SHOW TAG KEYS by approximately one hour using a 1h shard group duration. To filter other meta data, replace SHOW TAG KEYS with SHOW TAG VALUES, SHOW SERIES, SHOW MEASUREMENTS, SHOW FIELD KEYS, and so on.

Example filtering SHOW TAG KEYS by time

  • Specify a shard duration on a new database or alter an existing shard duration. To specify a 1h shard duration when creating a new database, run the following command:
  1. > CREATE database mydb with duration 7d REPLICATION 1 SHARD DURATION 1h name myRP;

Note: The minimum shard duration is 1h.

  • Verify the shard duration has the correct time interval (precision) by running the SHOW SHARDS command. The example below shows a shard duration with an hour precision.
  1. > SHOW SHARDS
  2. name: mydb
  3. id database retention_policy shard_group start_time end_time expiry_time owners
  4. -- -------- ---------------- ----------- ---------- -------- ----------- ------
  5. > precision h
  • (Optional) Insert sample tag keys. This step is for demonstration purposes. If you already have tag keys (or other meta data) to search for, skip this step.
  1. // Insert a sample tag called "test_key" into the "test" measurement, and then check the timestamp:
  2. > INSERT test,test_key=hello value=1
  4. > select * from test
  5. name: test
  6. time test_key value
  7. ---- -------- -----
  8. 434820 hello 1
  10. // Add new tag keys with timestamps one, two, and three hours earlier:
  12. > INSERT test,test_key_1=hello value=1 434819
  13. > INSERT test,test_key_2=hello value=1 434819
  14. > INSERT test,test_key_3_=hello value=1 434818
  15. > INSERT test,test_key_4=hello value=1 434817
  16. > INSERT test,test_key_5_=hello value=1 434817
  • To find tag keys within a shard duration, run one of the following commands:

SHOW TAG KEYS ON database-name <WHERE time clause> OR

SELECT * FROM measurement <WHERE time clause>

The examples below use test data from step 3.

  1. //Using data from Step 3, show tag keys between now and an hour ago
  2. > SHOW TAG KEYS ON mydb where time > now() -1h and time < now()
  3. name: test
  4. tagKey
  5. ------
  6. test_key
  7. test_key_1
  8. test_key_2
  10. // Find tag keys between one and two hours ago
  11. > SHOW TAG KEYS ON mydb where > time > now() -2h and time < now()-1h
  12. name: test
  13. tagKey
  14. ------
  15. test_key_1
  16. test_key_2
  17. test_key_3
  19. // Find tag keys between two and three hours ago
  20. > SHOW TAG KEYS ON mydb where > time > now() -3h and time < now()-2h
  21. name: test
  22. tagKey
  23. ------
  24. test_key_3
  25. test_key_4
  26. test_key_5
  28. // For a specified measurement, find tag keys in a given shard by specifying the time boundaries of the shard
  29. > SELECT * FROM test WHERE time >= '2019-08-09T00:00:00Z' and time < '2019-08-09T10:00:00Z'
  30. name: test
  31. time test_key_4 test_key_5 value
  32. ---- ------------ ------------ -----
  33. 434817 hello 1
  34. 434817 hello 1
  36. // For a specified database, find tag keys in a given shard by specifying the time boundaries of the shard
  37. > SHOW TAG KEYS ON mydb WHERE time >= '2019-08-09T00:00:00Z' and time < '2019-08-09T10:00:00Z'
  38. name: test
  39. tagKey
  40. ------
  41. test_key_4
  42. test_key_5