how mysql handle multiple START TRANSACTION (nesting?) [duplicate]

Question

I can't find the answer : how MySQL handle when in the same connection I call multiple time START TRANSACTION

for example does the autocommit the current one in order to start a fresh new or does he nest them?

NB : this is not a duplicate of Are nested transactions allowed in MySQL? because I don't whant to know if mysql allow it, or how to simulate this behaviou. I found that mysql does not nest the transactions and I want to know how MySQL actually handle nested START TRANSACTION (by commiting the old one, by ignoring the new start transaction, ...)

Answer 1

Read the manual instead of wikipedia.

First entry from googling "mysql start transaction":

13.3.1 START TRANSACTION, COMMIT, and ROLLBACK Syntax

Beginning a transaction causes any pending transaction to be committed. See Section 13.3.3, “Statements That Cause an Implicit Commit”, for more information.