MySQL has worse guarantees in several cases, though. For example, using `SERIALIZABLE` isolation means your queries can deadlock when run in parallel.
Likewise, selecting a column not present in a GROUP BY leads to random values being returned.
Likewise, selecting a column not present in a GROUP BY leads to random values being returned.
That hasn't been the default behavior for something like 5 years.
Beyond that the values aren't "random" as much as "one of the values from the set" which can be a useful feature in cares where you want any of the values and don't want the performance hit that comes with using an aggregate function particularly on very very large sets.