GROUP BY, or at least to make it harder for query writing developers to be burned by it.
For a long time now, MySQL has contained a notorious nonstandard extension to
GROUP BY, which allows oddball behavior in the name of efficiency. This extension has allowed countless developers around the world to use
GROUP BY in production code without completely understanding what they were doing.
In particular, it's a bad idea to use
SELECT * in a
GROUP BY query, because a standard
GROUP BY clause requires enumerating the columns. Many developers have, unfortunately, done that.
Read this. https://dev.mysql.com/doc/refman/5.7/en/group-by-handling.html
The MySQL team has been trying to fix this misfeature without messing up production code. They added a
sql_mode flag in 5.7.5 named
ONLY_FULL_GROUP_BY to compel standard behavior. In a recent release, they turned on that flag by default. When you upgraded your local MySQL to 5.7.14, the flag got switched on and your production code, dependent on the old extension, stopped working.
If you've recently started getting 1055 errors, what are your choices?
sql_modeto get rid of the newly set
You can change the mode by doing a
SET sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION'
should do the trick if you do it right after your application connects to MySQL.
Or, you can find the init file in your MySQL installation, locate the
sql_mode= line, and change it to omit
ONLY_FULL_GROUP_BY, and restart your server.