Data Manipulation Language

The BigQuery Data Manipulation Language (DML) enables you to update, insert, and delete data from your BigQuery tables.

You can execute DML statements just as you would a SELECT statement, with the following conditions:

  • You must use standard SQL. To enable standard SQL, see Switching SQL dialects.

  • You cannot specify a destination table. For example, in the web UI you must have Destination Table set to No table selected.

    Screenshot of BigQuery web UI showing no destination table selected

Limitations

  • Each DML statement initiates an implicit transaction, which means that changes made by the statement are automatically committed at the end of each successful DML statement. There is no support for multi-statement transactions.

  • Rows that were written to a table recently via streaming (using the tabledata.insertall method) cannot be modified using UPDATE, DELETE, or MERGE statements. Recent writes are typically those that occur within the last 30 minutes. Note that all other rows in the table remain modifiable by using UPDATE, DELETE, or MERGE statements.

  • Correlated subqueries within a when_clause, search_condition, merge_update_clause or merge_insert_clause are not supported for MERGE statements.

  • Queries that contain Data Manipulation Language (DML) statements cannot use a wildcard table as the target of the query. For example, a wildcard table may be used in the FROM clause of an UPDATE query, but a wildcard table cannot be used as the target of the UPDATE operation.

Concurrent jobs

BigQuery manages the concurrency of DML statements that add or modify or delete rows in a table.

INSERT DML concurrency

During any 24 hour period, the first 1000 statements that INSERT into a table will run concurrently. After this limit is reached, the concurrency of INSERT statements that write to a table is limited to 10. Any INSERT DML jobs beyond 10 are queued in PENDING state. After a previous job finishes, the next PENDING job is dequeued and run. Currently, up to 100 INSERT DML statements can be queued against a table at any given time.

UPDATE, DELETE, MERGE DML concurrency

We refer to UPDATE, DELETE, and MERGE DML statements as mutating DML statements. When you submit more than one mutating DML statement simultaneously to a table, BigQuery runs a fixed number of these statements concurrently. Any additional mutating DML jobs against that table are automatically queued in PENDING state. When a previously running job finishes, the next PENDING job is dequeued and run.

INTERACTIVE priority DML jobs that are queued for more than 6 hours will fail.

DML statement conflicts

Concurrently running mutating DML statements on a table might fail due to conflicts in the changes they make. BigQuery retries these failures.

  • An INSERT DML statement that inserts rows to a table will not conflict with any other concurrently running DML statement.

  • MERGE DML statements that contain only an INSERT clause with no UPDATE or DELETE clauses will not conflict with any other concurrently running DML statement.

  • MERGE DML statements with UPDATE or DELETE clauses will not conflict with any other concurrently running DML statement as long the MERGE statement does not lead to update or deletion of existing rows.

Pricing

For information on DML pricing, see Data Manipulation Language pricing on the Pricing page.

What's next

  • See DML syntax and samples on the DML syntax page.