This page introduces you to updating and deleting data in BigQuery
tables using DML. This page does not cover adding rows to existing tables using
DML. For information on adding rows using DML, see
in the DML syntax reference.
Follow along with the instructions below by using this sample file, which represents a table with an IP address column that you'd like to mask for anonymization:
The following steps load the sample data into a table and update the values
Step 1. Load the JSON file into a
Step 2. To mask the last octet in every row's
ip_address column, run the following
#standardSQL UPDATE sample_db.UserSessions SET ip_address = REGEXP_REPLACE(ip_address, r"(\.[0-9]+)$", ".0") WHERE TRUE
Follow along with the instructions below by using the sample files, which represent a dataset with multiple tables of analytics for user sessions and a table of users to be deleted.
The following steps load the data into three tables, and then delete the users listed in the DeletedUsers table.
Step 1. Load the JSON files into the DeletedUsers, Users, and UserSessions tables, respectively.
- Open the Google BigQuery web UI.
- Hover over your dataset ID.
- Click the arrow next to your dataset ID.
- Click Create new table.
- Select File upload for the Location.
- Select JSON (newline delimited) for the File format.
- Choose the Table name.
Under Schema enter a Name for each column in the table and select the appropriate Type.
- Click Add field and repeat until you have entered all the columns in your table.
Click Create table.
The schemas for the sample tables are:
To use the bq command-line tool to create
the tables, use the
bq load command. Supply the
and set the value to your location. The
--location flag is optional. For example, if you are using BigQuery
asia-northeast1 (Tokyo) region, the load command would look like the
bq --location=asia-northeast1 load ...
To create the
bq --location=asia-northeast1 load --source_format=NEWLINE_DELIMITED_JSON \ sample_db.DeletedUsers \ deletedUsersData.json \ id:integer
To create the
bq --location=asia-northeast1 load --source_format=NEWLINE_DELIMITED_JSON \ sample_db.Users \ usersData.json \ id:integer,date_joined:timestamp
To create the
bq --location=asia-northeast1 load --source_format=NEWLINE_DELIMITED_JSON \ sample_db.UserSessions \ userSessionsData.json \ id:string,user_id:integer,login_time:timestamp,logout_time:timestamp,ip_address:string
Step 2. To delete the information about the users in the DeletedUsers table. Run the following DML queries:
Delete from UsersSessions
#standardSQL DELETE FROM sample_db.UserSessions WHERE user_id in (SELECT id from sample_db.DeletedUsers)
Delete from Users
#standardSQL DELETE FROM sample_db.Users WHERE id in (SELECT id from sample_db.DeletedUsers)