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sql-statement-start-transaction.md

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title START TRANSACTION | TiDB SQL Statement Reference
summary An overview of the usage of START TRANSACTION for the TiDB database.
aliases
/docs/dev/sql-statements/sql-statement-start-transaction/
/docs/dev/reference/sql/statements/start-transaction/

START TRANSACTION

This statement starts a new transaction inside of TiDB. It is similar to the statement BEGIN.

In the absence of a START TRANSACTION statement, every statement will by default autocommit in its own transaction. This behavior ensures MySQL compatibility.

Synopsis

BeginTransactionStmt:

BeginTransactionStmt

Examples

mysql> CREATE TABLE t1 (a int NOT NULL PRIMARY KEY);
Query OK, 0 rows affected (0.12 sec)

mysql> START TRANSACTION;
Query OK, 0 rows affected (0.00 sec)

mysql> INSERT INTO t1 VALUES (1);
Query OK, 1 row affected (0.00 sec)

mysql> COMMIT;
Query OK, 0 rows affected (0.01 sec)

MySQL compatibility

This statement is understood to be partly compatible with MySQL.

  • START TRANSACTION is equivalent to MySQL’s START TRANSACTION WITH CONSISTENT SNAPSHOT, that is, after START TRANSACTION, a SELECT statement (not SELECT FOR UPDATE) is executed to read data from any table in InnoDB.
  • READ ONLY and its extended options are only syntactically compatible, and its effect is equivalent to START TRANSACTION.

Any compatibility differences should be reported via an issue on GitHub.

See also