which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

When executing a colleague's sql, I found that group by has a problem.

select max(id) as id,c_service_time,c_adress,c_rfid_sign from t_records group by c_rfid_sign;

The reason is that after 5.7, mysql sql_mode has ONLY_FULL_GROUP_BY mode limitation, that is, the query column must be in group by, or aggregate column (using max, min, avg, sum aggregate function)

There are two types of solutions

First, modify the sql sql_mode settings

First, you can execute the following command to view the sql_mode settings.

1、SHOW SESSION VARIABLES;

2、SHOW GLOBAL VARIABLES;
3、select @@sql_mode;

The result is ONLY_FULL_GROUP_BY, STRICT_TRANS_TABLES, NO_ZERO_IN_DATE, NO_ZERO_DATE, ERROR_FOR_DIVISION_BY_ZERO, NO_ENGINE_SUBSTITUTION

Run the following command to modify sql_mode.

set session sql_mode='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';

set global sql_mode='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';


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';

 

Second, modify the query sql

select * from t_records where id in(select max(id) from t_records group by c_rfid_sign );

select * from t_records a where not exists( select * from t_records b where a.c_rfid_sign=b.c_rfid_sign and a.id<b.id);

 

Third, sql_mode description

ReferenceMySQL Query: Order by Clause Is Not in Group by..this is incompatible with sql_mode = only_full_group_by

ONLY_FULL_GROUP_BY: For a GROUP BY aggregate operation, if the column in the SELECT is not in the GROUP
appears in BY, then this SQL is not legal, because the column is not in the GROUP BY clause

NO_AUTO_VALUE_ON_ZERO: This value affects the insertion of self-growth columns. By default, inserting 0 or NULL represents the next self-growth value. If the user
The value you want to insert is 0, and the column is self-growth, so this option is useful.

STRICT_TRANS_TABLES: In this mode, if a value cannot be inserted into a transaction table, the current operation is interrupted, and no restrictions are imposed on the non-transactional table.
NO_ZERO_IN_DATE: In strict mode, dates and months are not allowed to be zero

NO_ZERO_DATE: Set this value, the mysql database does not allow the insertion of a zero date, inserting a zero date will throw an error instead of a warning.

ERROR_FOR_DIVISION_BY_ZERO: In the INSERT or UPDATE process, if the data is divided by zero, an error is generated instead of a warning. Such as
If this mode is not given, then MySQL returns NULL when the data is divided by zero.

NO_AUTO_CREATE_USER: Disable GRANT to create a user with a blank password

NO_ENGINE_SUBSTITUTION：
An error is thrown if the required storage engine is disabled or not compiled. When this value is not set, replace it with the default storage engine and throw an exception

PIPES_AS_CONCAT：
treats "||" as a string concatenation operator instead of an OR operator, which is the same as the Oracle database, and is similar to the string concatenation function Concat.

ANSI_QUOTES: After ANSI_QUOTES is enabled, double quotes cannot be used to reference a string because it is interpreted as an identifier