1. Reason

Such an error in aggregate query is because the mode set by mysql contains ONLY_FULL_GROUP_BY

mysql> select @@sql_mode;
+-------------------------------------------------------------------------------------------------------------------------------------------+
| @@sql_mode                                                                                                                                |
+-------------------------------------------------------------------------------------------------------------------------------------------+
| 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 |
+-------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Two, modify

Modify in the configuration file

 

sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

mysql> select @@sql_mode;
+------------------------------------------------------------------------------------------------------------------------+
| @@sql_mode                                                                                                             |
+------------------------------------------------------------------------------------------------------------------------+
| STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Then restart the service

 

Three, cause analysis

According to the examples on the Internet, I reproduced it myself. Reference materials:、

 

I created a table in the database, game, with the following data

 

When I execute the following sql statement, an error occurs

sql statement: select name, group_id from game group by group_id;

error:

1055 - Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 't.game.name' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

 

If ONLY_FULL_GROUP_BY is removed, no error will be reported

 

The meaning of the sql statement is to sort by group, but there are two records in group B here, and I don't know which one to return, so an error is reported.

In fact, there will be no problem with mysql. Such an error can only mean that there is a problem with the sql statement we wrote.

Four, appendix

 

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 non-transactional tables
NO_ZERO_IN_DATE：
   In strict mode, dates with a month or day part of 0 are not accepted. If the IGNORE option is used, we insert '0000-00-00' for similar dates. In non-strict mode, the date can be accepted, but a warning will be generated.
NO_ZERO_DATE：
 In strict mode, do not use '0000-00-00' as a legal date. You can still insert zero dates with the IGNORE option. In non-strict mode, the date can be accepted, but a warning will be generated
ERROR_FOR_DIVISION_BY_ZERO：
 In strict mode, during INSERT or UPDATE, if it is divided by zero (or MOD(X, 0)), an error is generated (otherwise it is a warning). If this mode is not given, MySQL returns NULL when dividing by zero. If you use INSERT IGNORE or UPDATE IGNORE, MySQL generates a division by zero warning, but the result of the operation is NULL
NO_AUTO_CREATE_USER：
 Prevent GRANT from automatically creating new users unless a password is also specified.
NO_ENGINE_SUBSTITUTION：
 If the required storage engine is disabled or not compiled, an error is thrown. When this value is not set, replace with the default storage engine and throw an exception