Are nested transactions allowed in MySQL?

Question

Does MySQL allow the use of nested transactions?

Answer 1

No, but

InnoDB supports SAVEPOINTS.

You can do the following:

CREATE TABLE t_test (id INT NOT NULL PRIMARY KEY) ENGINE=InnoDB;

START TRANSACTION;

INSERT
INTO    t_test
VALUES  (1);

SELECT  *
FROM    t_test;

 id
---
  1

SAVEPOINT tran2;

INSERT
INTO    t_test
VALUES  (2);

SELECT  *
FROM    t_test;

 id
---
  1
  2

ROLLBACK TO tran2;

SELECT  *
FROM    t_test;

 id
---
  1

ROLLBACK;

SELECT  *
FROM    t_test;

 id
---

Answer 2

From MySQL documentation:

Transactions cannot be nested. This is a consequence of the implicit commit performed for any current transaction when you issue a START TRANSACTION statement or one of its synonyms. https://dev.mysql.com/doc/refman/5.7/en/implicit-commit.html