druid/docs/content/SelectQuery.md

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2014-04-22 18:27:19 -04:00
---
layout: doc_page
---
# Select Queries
Select queries return raw Druid rows and support pagination.
```json
{
"queryType": "select",
"dataSource": "wikipedia",
"dimensions":[],
"metrics":[],
"granularity": "all",
"intervals": [
"2013-01-01/2013-01-02"
],
"pagingSpec":{"pagingIdentifiers": {}, "threshold":5}
}
```
There are several main parts to a select query:
|property|description|required?|
|--------|-----------|---------|
|queryType|This String should always be "select"; this is the first thing Druid looks at to figure out how to interpret the query|yes|
|dataSource|A String defining the data source to query, very similar to a table in a relational database|yes|
|intervals|A JSON Object representing ISO-8601 Intervals. This defines the time ranges to run the query over.|yes|
|dimensions|The list of dimensions to select. If left empty, all dimensions are returned.|no|
|metrics|The list of metrics to select. If left empty, all metrics are returned.|no|
|pagingSpec|A JSON object indicating offsets into different scanned segments. Select query results will return a pagingSpec that can be reused for pagination.|yes|
|context|An additional JSON Object which can be used to specify certain flags.|no|
The format of the result is:
```json
[{
"timestamp" : "2013-01-01T00:00:00.000Z",
"result" : {
"pagingIdentifiers" : {
"wikipedia_2012-12-29T00:00:00.000Z_2013-01-10T08:00:00.000Z_2013-01-10T08:13:47.830Z_v9" : 4
},
"events" : [ {
"segmentId" : "wikipedia_editstream_2012-12-29T00:00:00.000Z_2013-01-10T08:00:00.000Z_2013-01-10T08:13:47.830Z_v9",
"offset" : 0,
"event" : {
"timestamp" : "2013-01-01T00:00:00.000Z",
"robot" : "1",
"namespace" : "article",
"anonymous" : "0",
"unpatrolled" : "0",
"page" : "11._korpus_(NOVJ)",
"language" : "sl",
"newpage" : "0",
"user" : "EmausBot",
"count" : 1.0,
"added" : 39.0,
"delta" : 39.0,
"variation" : 39.0,
"deleted" : 0.0
}
}, {
"segmentId" : "wikipedia_2012-12-29T00:00:00.000Z_2013-01-10T08:00:00.000Z_2013-01-10T08:13:47.830Z_v9",
"offset" : 1,
"event" : {
"timestamp" : "2013-01-01T00:00:00.000Z",
"robot" : "0",
"namespace" : "article",
"anonymous" : "0",
"unpatrolled" : "0",
"page" : "112_U.S._580",
"language" : "en",
"newpage" : "1",
"user" : "MZMcBride",
"count" : 1.0,
"added" : 70.0,
"delta" : 70.0,
"variation" : 70.0,
"deleted" : 0.0
}
}, {
"segmentId" : "wikipedia_2012-12-29T00:00:00.000Z_2013-01-10T08:00:00.000Z_2013-01-10T08:13:47.830Z_v9",
"offset" : 2,
"event" : {
"timestamp" : "2013-01-01T00:00:00.000Z",
"robot" : "0",
"namespace" : "article",
"anonymous" : "0",
"unpatrolled" : "0",
"page" : "113_U.S._243",
"language" : "en",
"newpage" : "1",
"user" : "MZMcBride",
"count" : 1.0,
"added" : 77.0,
"delta" : 77.0,
"variation" : 77.0,
"deleted" : 0.0
}
}, {
"segmentId" : "wikipedia_2012-12-29T00:00:00.000Z_2013-01-10T08:00:00.000Z_2013-01-10T08:13:47.830Z_v9",
"offset" : 3,
"event" : {
"timestamp" : "2013-01-01T00:00:00.000Z",
"robot" : "0",
"namespace" : "article",
"anonymous" : "0",
"unpatrolled" : "0",
"page" : "113_U.S._73",
"language" : "en",
"newpage" : "1",
"user" : "MZMcBride",
"count" : 1.0,
"added" : 70.0,
"delta" : 70.0,
"variation" : 70.0,
"deleted" : 0.0
}
}, {
"segmentId" : "wikipedia_2012-12-29T00:00:00.000Z_2013-01-10T08:00:00.000Z_2013-01-10T08:13:47.830Z_v9",
"offset" : 4,
"event" : {
"timestamp" : "2013-01-01T00:00:00.000Z",
"robot" : "0",
"namespace" : "article",
"anonymous" : "0",
"unpatrolled" : "0",
"page" : "113_U.S._756",
"language" : "en",
"newpage" : "1",
"user" : "MZMcBride",
"count" : 1.0,
"added" : 68.0,
"delta" : 68.0,
"variation" : 68.0,
"deleted" : 0.0
}
} ]
}
} ]
```
The result returns a global pagingSpec that can be reused for the next select query. The offset will need to be increased by 1 on the client side.