【MySQL】err Error 1055 Expression #2 of SELECT list is not in GROUP BY clause… sql_mode=only_full_group_by ...

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MySQL 版本：

$ brew info mysql
mysql: stable 5.7.21 (bottled), devel 8.0.4-rc
Open source relational database management system
https://dev.mysql.com/doc/refman/5.7/en/
Conflicts with:
  mariadb (because mysql, mariadb, and percona install the same binaries.)
  mariadb-connector-c (because both install plugins)
  mysql-cluster (because mysql, mariadb, and percona install the same binaries.)
  mysql-connector-c (because both install MySQL client libraries)
  percona-server (because mysql, mariadb, and percona install the same binaries.)
/usr/local/Cellar/mysql/5.7.21 (323 files, 235.0MB) *
  Poured from bottle on 2018-03-13 at 16:09:50
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/mysql.rb

问题

使用 sql 查询时 mysql 报如下错误，
完整报错如下：

err:Error 1055: Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'projectkdb.detail_local.name' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by ctx:context.Ba ckground.WithValue(1, “505b934")

经查，是由于默认的 MySQL 配置中 sql_mode 配置了 only_full_group，需要 GROUP BY 中包含所有 在 SELECT 中出现的字段。因此需要在 MySQL 的配置中去掉这个配置。

使用 SQL 语句可以查询这个配置：

select @@sql_mode;

解决方法

在 配置文件（my.cnf）中 修改 sql_mode 的配置为：

$ vim /usr/local/etc/my.cnf
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

具体的配置文件的位置请参照：

【MySQL】Mac 上使用 brew 安装的 mysql 配置文件位置