最近把mysql 升级到了5.7.18 然后就发现了一个很明显的变化, ONLY_FULL_GROUP_BY 这个mysql mode 被加了进来, 按照sql 99 的标准这是好事.

但是实际上, mysql 的这个版本只能说almost identical or very close to, 不能说完全相等


That is, MySQL 5.7.5m15 will by default reject only those GROUP 
BY-queries that include non-aggregated expressions in the SELECT-list that 
are not functionally dependent upon the GROUP BY-list.

This not only means that you cannot mess up your GROUP BY-queries anymore 
(as MySQL will now reject an improper GROUP BY query), 
it will also not require you to write non-sensical "dummy" aggregates
 over expressions that can only have one value per aggregated 
result row. Hurrah!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

This site uses Akismet to reduce spam. Learn how your comment data is processed.