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Comment by kbsletten | Hacker News Reader

I have to say, I wouldn't get your hopes up. If I were MySQL, I wouldn't touch this with a 10 ft pole because it's not likely to really affect somebody's opinion of MySQL enough to switch, but there's going to be at least one person whose code you'll break. Before you can consider SQL compatibility, you have to keep most-popular-version-of-mysql compatibility.

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Hi! Former MySQL Product Manager here. I'm not sure I ever looked at this issue specifically, but you are correct: the burden of breaking backwards compatibility should be high, and supported by major use cases.

To give a similar example, that I did look at: MySQL can enable more standards equivalent identifier quoting (via an SQL mode): https://dev.mysql.com/doc/refman/5.7/en/sql-mode.html#sqlmod...

To enable that by default would break a lot of applications.

I agree. If it's desired, use a config setting to make it the default. It was already standard practice in any MySQL database I rolled out to set InnoDB as the default storage engine in the config until it became the shipped default. Like transaction isolation levels, this is something you either set as an administrator for your need, or you let the application setup guide steer you, or you let the application queries specifically set it, if the application needs it. Otherwise,you risk causing real data corruption and loss to existing customers purely for the benefit of being more compliant in your default configuration.

A global and per-session setting is sufficient and more beneficial, IMO, so I think MariaDB took the right approach. If MySQL still doesn't have that setting, well, that's troubling, but I can't say I'm entirely surprised.

MariaDB and MySQL have different goals here - MariaDB wants to offer drop-in compatibility for Oracle. MySQL has a core-audience of OLTP apps, that are mostly developed for it specifically.

When designing features, I think it's important to make sure they can benefit the highest number of users possible. For this one, I don't think it can ever be the default because of the burden of backward compatibility. So it is difficult to justify developing it.

I don't see the problem here. Make the default preserve backward compatibility, but offer an option like 'SIMULTANEOUS_ASSIGNMENT' to be standards-compliant.

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