The order of the results of a `SELECT` query are **never** guaranteed when there's no `ORDER BY` clause specified. This is true in pretty much all modern relational database systems (as per the SQL standard).

You can find more information specific to MySQL in [this DBA.StackExchange.com answer](https://dba.stackexchange.com/a/6053/150011):

> In the SQL world, order is not an inherent property of a set of data. Thus, you get no guarantees from your RDBMS that your data will come back in a certain order -- or even in a consistent order -- unless you query your data with an ORDER BY clause.
>
> - MySQL sorts the records however it wants without any guarantee of consistency.
> - If you intend to rely on this order for anything, **you must specify your desired order using ORDER BY. To do anything else is to set yourself up for unwelcome surprises.**

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To your question "*«Then why is it always the last one?»*":

You can almost attribute this to luck, on repeated runs. As mentioned above "*MySQL sorts the records however it wants*". What this really means is that the algorithm of the database engine returns the rows based on the results of a multitude of operations that it goes through *under the hood*. For now, it appears to be in a repeatable order, but because of the complexity of the database engine and that promised *lack of guarantee* without an `ORDER BY` clause, it will not always be repeatable and can change for a multitude of reasons, unexpectedly. So you should not rely on the ordering you see today to be the same one you'll see in the future.