Group Statements Into A Transaction

Use `BEGIN`, `COMMIT`, and `ROLLBACK` to execute multiple statements as an atomic unit.

5/5 supported engines validation-green 1 example 2 scenarios

Docker-validated Not currently validation-green

Example 1

Transfer funds between accounts atomically

Alice's balance decreases by 100 and Bob's increases by 100. Both updates are committed together. If either update had failed, a ROLLBACK would have reverted both — keeping the total balance consistent. Replace COMMIT with ROLLBACK to undo both changes instead.

MySQL MariaDB

Engine-specific syntax

Source table data

Setup

CREATE TABLE accounts (id INT, name VARCHAR(50), balance INT);

INSERT INTO
  accounts (id, name, balance)
VALUES
  (1, 'Alice', 1000),
  (2, 'Bob', 500);

Validated query

SQL

START TRANSACTION;

UPDATE accounts
SET
  balance = balance - 100
WHERE
  id = 1;

UPDATE accounts
SET
  balance = balance + 100
WHERE
  id = 2;

COMMIT;

SELECT
  id,
  name,
  balance
FROM
  accounts
ORDER BY
  id;

Expected result

id	name	balance
1	Alice	900
2	Bob	600

SQL Server

Engine-specific syntax

Source table data

Setup

CREATE TABLE accounts (id INT, name VARCHAR(50), balance INT);

INSERT INTO
  accounts (id, name, balance)
VALUES
  (1, 'Alice', 1000),
  (2, 'Bob', 500);

Validated query

SQL

BEGIN TRANSACTION;

UPDATE accounts
SET
  balance = balance - 100
WHERE
  id = 1;

UPDATE accounts
SET
  balance = balance + 100
WHERE
  id = 2;

COMMIT;

SELECT
  id,
  name,
  balance
FROM
  accounts
ORDER BY
  id;

Expected result

id	name	balance
1	Alice	900
2	Bob	600

PostgreSQL SQLite

Engine-specific syntax

Source table data

Setup

CREATE TABLE accounts (id INT, name VARCHAR(50), balance INT);

INSERT INTO
  accounts (id, name, balance)
VALUES
  (1, 'Alice', 1000),
  (2, 'Bob', 500);

Validated query

SQL

BEGIN;

UPDATE accounts
SET
  balance = balance - 100
WHERE
  id = 1;

UPDATE accounts
SET
  balance = balance + 100
WHERE
  id = 2;

COMMIT;

SELECT
  id,
  name,
  balance
FROM
  accounts
ORDER BY
  id;

Expected result

id	name	balance
1	Alice	900
2	Bob	600

SQL Server uses BEGIN TRANSACTION, MySQL/MariaDB use START TRANSACTION, and PostgreSQL uses BEGIN. The resulting data is identical across engines.

Useful when

Where this command helps.

grouping multiple updates so they all succeed or all fail together
safely transferring value between rows without partial state

Explanation

What the command is doing.

A transaction groups multiple SQL statements so they either all succeed or all fail together. BEGIN (or START TRANSACTION / BEGIN TRANSACTION) opens the transaction. COMMIT applies all changes permanently. ROLLBACK discards all changes made since BEGIN, leaving the data unchanged. Transactions prevent partial updates — for example, if a funds transfer debits one account but crashes before crediting another, a rollback restores both accounts to their original state.

Group Statements Into A Transaction

Transfer funds between accounts atomically

Where this command helps.

What the command is doing.

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