标签：aggregate only blog str 是什么 ict select his variables
1. 判断是否是空值 is not null 和 is null
select * from XXX where column_name is not null;
select * from XXX where column_1 is not null and column_2 is not null;
2. [Err] 1055 - Expression #1 of ORDER BY clause is not in GROUP BY clause and contains nonaggregated column ‘information_schema.PROFILING.SEQ‘ which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
原因：由 sql_mode 引起的。
SHOW VARIABLES LIKE ‘%sql_mode%‘; 或者 select version(), @@sql_mode; 都能看到sql_mode的value值是什么，可以见到它的值是：
ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
也就是存在：ONLY_FULL_GROUP_BY
解决方法：
执行：SET sql_mode=(SELECT REPLACE(@@sql_mode,‘ONLY_FULL_GROUP_BY‘,‘‘));
参考：
https://www.cnblogs.com/acmexyz/p/10831536.html
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标签：aggregate only blog str 是什么 ict select his variables
原文地址：https://www.cnblogs.com/qi-yuan-008/p/12198767.html
