The influence of mysql database sql_mode mode

Execute the following SQL in mysql today

SELECT title AS name,sum(buy_number) AS value FROM `s_order_detail` GROUP BY `goods_id` ORDER BY `value` DESC LIMIT 10 ;

The following error broke out:

/* SQL Error (1055): Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'shopxo.s_order_detail.title' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by */

After Baidu found out that MySQL has multiple sql_mode modes

ONLY_FULL_GROUP_BY：  
对于GROUP BY聚合操作，如果在SELECT中的列，没有在GROUP BY中出现，那么这个SQL是不合法的，因为列不在GROUP BY从句中 
 
NO_AUTO_VALUE_ON_ZERO：  
该值影响自增长列的插入。默认设置下，插入0或NULL代表生成下一个自增长值。如果用户 希望插入的值为0，而该列又是自增长的，那么这个选项就有用了。 
 
STRICT_TRANS_TABLES：  
在该模式下，如果一个值不能插入到一个事务表中，则中断当前的操作，对非事务表不做限制 
 
NO_ZERO_IN_DATE：  
在严格模式下，不允许日期和月份为零 
 
NO_ZERO_DATE：  
设置该值，mysql数据库不允许插入零日期，插入零日期会抛出错误而不是警告。 
 
ERROR_FOR_DIVISION_BY_ZERO：  
在INSERT或UPDATE过程中，如果数据被零除，则产生错误而非警告。如 果未给出该模式，那么数据被零除时MySQL返回NULL 
 
NO_AUTO_CREATE_USER：  
禁止GRANT创建密码为空的用户 
 
NO_ENGINE_SUBSTITUTION：  
如果需要的存储引擎被禁用或未编译，那么抛出错误。不设置此值时，用默认的存储引擎替代，并抛出一个异常 
 
PIPES_AS_CONCAT：  
将”||”视为字符串的连接操作符而非或运算符，这和Oracle数据库是一样的，也和字符串的拼接函数Concat相类似  
ANSI_QUOTES：  
启用ANSI_QUOTES后，不能用双引号来引用字符串，因为它被解释为识别符

Discovered by executing the command on the command line:

So how to solve this problem? 1, 2 are not recommended, recommended method 3

1. Use a ny_value() function, this function is effective for fields that do not require group by, which is equivalent to turning off only_full_group_by, but this will inevitably miss a field, so it is not recommended.

2. Temporarily close (you can check sql_mode through select @@sql_mode and remove ONLY_FULL_GROUP_BY and copy it ) :

set sql_mode=' '//Change the existing database sql_mode

set @@global.sql_mode=' '//Change the global configuration sql_mode

The above configuration becomes invalid after restarting the service

3. Change the configuration file (recommended)

Linux system changes the /etc/my.cnf file, Windows system changes the /etc/my.ini file

Modify under mysqld

Finally, after testing, the problem was solved.

SELECT title AS name,sum(buy_number) AS value FROM `s_order_detail` GROUP BY `goods_id` ORDER BY `value` DESC LIMIT 10 ;
/* Affected rows: 0 Found rows: 2 Warning: 0 Duration for 1 Query: 0.000 sec. */

The influence of mysql database sql_mode mode

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