How to Import CSV Files into BigQuery Quickly

Galaxy Glossary

How do I import a CSV file into BigQuery?

Loads a local or Cloud Storage–hosted CSV file into a BigQuery table via bq CLI, Web UI, or scheduled job.

Welcome to the Galaxy, Guardian!
You'll be receiving a confirmation email

Follow us on twitter :)

Oops! Something went wrong while submitting the form.

Description

Example H2

Example H3

Why import a CSV into BigQuery?

CSV remains the fastest way to bulk-load data from spreadsheets, exports, or third-party tools into BigQuery when APIs aren’t available.It lets analysts start querying immediately without writing ETL code.

Which methods can I use?

Choose between the bq CLI for automation, the Cloud Console for ad-hoc loads, or Scheduled Queries to refresh the table on a timetable.

How do I import a CSV with the bq CLI?

Run bq load with --source_format=CSV, supply your schema, and point to a local file or gs:// URI.Use --autodetect to infer column types fast.

Example with explicit schema

The command below loads customers.csv into ecom.Customers, skips headers, keeps nulls, and creates the table if needed.

bq load --source_format=CSV \ --skip_leading_rows=1 \ --field_delimiter="," \ --allow_quoted_newlines \ ecom.Customers \ id:INT64,name:STRING,email:STRING,created_at:TIMESTAMP \ gs://galaxy_uploads/customers.csv

How do I import a CSV via the Cloud Console?

Inside BigQuery, click “Create Table,” pick “Upload” or “Cloud Storage,” select CSV, toggle “Auto detect,” and confirm.The UI mirrors CLI flags under the hood.

Can I schedule recurring CSV loads?

Create a Cloud Storage bucket with daily drops, then add a Scheduled Query or Cloud Scheduler + Cloud Functions job that triggers the same bq load command.

Best practices

• Compress files with GZIP to cut transfer time.
• Match column order between CSV and schema.
• Use UTC timestamps to avoid daylight-savings surprises.

Common mistakes

Dropping the header row but forgetting --skip_leading_rows=1 causes BigQuery to treat column names as data.
Uploading a local file larger than 10 MB in the UI fails; move it to Cloud Storage first.

Need to verify the load?

Run SELECT COUNT(*) FROM ecom.Customers; to confirm row count, or inspect the Load Job history for errors and bytes processed.

Why How to Import CSV Files into BigQuery Quickly is important

How to Import CSV Files into BigQuery Quickly Example Usage


bq load --source_format=CSV --autodetect --skip_leading_rows=1 \
  ecom.OrderItems \
  gs://galaxy_uploads/order_items.csv

How to Import CSV Files into BigQuery Quickly Syntax


bq load [FLAGS] <project_id>:<dataset>.<table> [PATH_TO_CSV]

Flags:
  --source_format=CSV                    # Required for CSV
  --skip_leading_rows=NUM                # Skip headers
  --field_delimiter=','                 # Column separator
  --quote='"'                           # Quote character
  --allow_quoted_newlines                # Handle embedded line breaks
  --autodetect                           # Infer schema
  --schema=field:type[,field:type...]    # Explicit schema
  --time_partitioning_field=created_at   # Optional partition key
  --replace                              # Overwrite existing table

Example (ecommerce):
bq load --source_format=CSV --skip_leading_rows=1 \
  ecom.Orders \
id:INT64,customer_id:INT64,order_date:DATE,total_amount:NUMERIC \
  gs://galaxy_uploads/orders_2024_03.csv

Common Mistakes

Forgetting --skip_leading_rows=1. BigQuery loads the header row as data, shifting types and causing query failures. Always add the flag when the first row is column names.
Relying on local uploads for large files. The Web UI limits local files to 10 MB; larger files must be staged in Cloud Storage, then referenced via gs:// URI.