# ReqBigQuery
[](https://hex.pm/packages/req_bigquery)
[Req](https://github.com/wojtekmach/req) plugin for [Google BigQuery](https://cloud.google.com/bigquery/docs/reference/rest).
ReqBigQuery makes it easy to make BigQuery queries. It uses [Goth](https://github.com/peburrows/goth)
for authentication. Query results are decoded into the `ReqBigQuery.Result` struct.
The struct implements the `Table.Reader` protocol and thus can be efficiently traversed by rows or columns.
## Usage
```elixir
Mix.install([
{:goth, "~> 1.3.0"},
{:req, "~> 0.3.5"},
{:req_bigquery, "~> 0.1.1"}
])
# We use Goth to authenticate to Google Cloud API.
# See: https://hexdocs.pm/goth/1.3.0-rc.4/Goth.Token.html#fetch/1-source for more information.
credentials = File.read!("credentials.json") |> Jason.decode!()
source = {:service_account, credentials, []}
{:ok, _} = Goth.start_link(name: MyGoth, source: source, http_client: &Req.request/1)
project_id = System.fetch_env!("PROJECT_ID")
# With plain string query
query = """
SELECT title, SUM(views) AS views
FROM `bigquery-public-data.wikipedia.table_bands`
WHERE EXTRACT(YEAR FROM datehour) <= 2021
GROUP BY title
ORDER BY views DESC
LIMIT 10
"""
req = Req.new() |> ReqBigQuery.attach(goth: MyGoth, project_id: project_id)
res = Req.post!(req, bigquery: query).body
#=>
# %ReqBigQuery.Result{
# columns: ["title", "views"],
# job_id: "job_JDDZKquJWkY7x0LlDcmZ4nMQqshb",
# num_rows: 10,
# rows: %Stream{}
# }
Enum.to_list(res.rows)
#=>
# [
# ["The_Beatles", 13758950],
# ["Queen_(band)", 12019563],
# ["Pink_Floyd", 9522503],
# ["AC/DC", 8972364],
# ["Led_Zeppelin", 8294994],
# ["Linkin_Park", 8242802],
# ["The_Rolling_Stones", 7825952],
# ["Red_Hot_Chili_Peppers", 7302904],
# ["Fleetwood_Mac", 7199563],
# ["Twenty_One_Pilots", 6970692]
# ]
# With parameterized query
query = """
SELECT EXTRACT(YEAR FROM datehour) AS year, SUM(views) AS views
FROM `bigquery-public-data.wikipedia.table_bands`
WHERE EXTRACT(YEAR FROM datehour) <= 2021
AND title = ?
GROUP BY year
ORDER BY views DESC
"""
req = Req.new() |> ReqBigQuery.attach(goth: MyGoth, project_id: project_id)
res = Req.post!(req, bigquery: {query, ["Linkin_Park"]}).body
#=>
# %ReqBigQuery.Result{
# columns: ["year", "views"],
# job_id: "job_GXiJvALNsTAoAOJ39Eg3Mw94XMUQ",
# num_rows: 7,
# rows: %Stream{}
# }
Enum.to_list(res.rows)
#=> [[2017, 2895889], [2016, 1173359], [2018, 1133770], [2020, 906538], [2015, 860899], [2019, 790747], [2021, 481600]]
```
## License
Copyright (C) 2022 Dashbit
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0)
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
