About laravel solving mysql only_full_group_by problem

The following column Laravel Tutorial will introduce to you how laravel solves the mysql only_full_group_by problem. I hope it will be helpful to friends in need!

After MySQL 5.7, only_full_group_by is enabled by default, which leads to more stringent SQL detection, which will lead to the following error being reported

SQLSTATE[42000]: Syntax error or access violation: 1055 Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'edu.t_sounds.id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

There is no way to solve this problem Avoid detours and try one by one according to the methods found online

Solution ideas

View sql_mode

select @@GLOBAL.sql_mode;SELECT @@SESSION.sql_mode

First check and modify the mysql configuration file. My.cnf is very embarrassing. There is no ONLY_FULL_GROUP_BY in my. According to the client configuration, add [client] configuration

[mysqld]sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

Restart mysql, check sql_mode in the MySQL tool, and the displayed result is indeed the same as the configuration, but the program still reports the same error

After another search, I suddenly realized the problem of global session, which is the two statements querying sql_mode at the top of the article. I asked what the difference is.

mysql variable settings There are two ways, One is global configuration, which is global, and acts on the whole world; One is session configuration session, which only acts on the current connection

Will it happen? It is laravel that has set sql_mode in the current connection.

When the laravel program prints sql_mode

[client]sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

Copy after login

, it turns out that it is the program that has set it.

The first thing that comes to mind is mysql There is a strict mode in the configuration. I have always turned it on and set it to false. The problem was solved smoothly

$result = \DB::select('SELECT @@GLOBAL.sql_mode');
print_r($result);exit;
结果：
STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION

$result = \DB::select('SELECT @@SESSION.sql_mode');
print_r($result);exit;
结果：
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

This can solve the problem, but based on technology, I just want to figure out how it is written, and I don’t want to Set it to false directly,

Search for strict in the vendor/laravel/framework/src/ILLuminate/Database folder, and directly find the core code
File: vendor/laravel/ framework/src/ILLuminate/Database/Connectors/MySqlConnector.php

'strict' => false,

The first judgment directly determines whether there is a modes configuration. If so, just use this

to do it

protected function setModes(PDO $connection, array $config){
    if (isset($config['modes'])) {
        $this->setCustomModes($connection, $config);
    } elseif (isset($config['strict'])) {
        if ($config['strict']) {
            $connection->prepare($this->strictMode($connection))->execute();
        } else {
            $connection->prepare("set session sql_mode='NO_ENGINE_SUBSTITUTION'")->execute();
        }
    }}

Test, solve the problem directly

In the spirit of searching for the root cause, then read on

If strict = true

will be set directly in the program The hard-coded sql_mode, laravel distinguishes mysql 8.0.11 from other versions

'modes' => ['STRICT_TRANS_TABLES', 'NO_ZERO_IN_DATE', 'NO_ZERO_DATE', 'ERROR_FOR_pISION_BY_ZERO', 'NO_AUTO_CREATE_USER', 'NO_ENGINE_SUBSTITUTION'],

Then if strict = false, directly set sql_mode to NO_ENGINE_SUBSTITUTION

protected function strictMode(PDO $connection)
{
    if (version_compare($connection->getAttribute(PDO::ATTR_SERVER_VERSION), '8.0.11') >= 0) {
        return "set session sql_mode='ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION'";
    }

    return "set session 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'";
}

The problem is completely solved here

Final solution

$connection->prepare("set session sql_mode='NO_ENGINE_SUBSTITUTION'")->execute();

Retain strict = true, add the modes option, the parameters inside are the underlying configuration of laravel, but only remove ONLY_FULL_GROUP_BY

Summary: After taking a lot of detours and spending a lot of time, the problem was finally solved, and there was no need to modify any configuration of mysql

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