关于laravel 子查询 & join的使用

本项目中关联了2个数据库'default'=>env('DB_CONNECTION','mysql'),//默认使用mysql为连接库'connections

本项目中关联了2个数据库

'default' => env('DB_CONNECTION', 'mysql'), //默认使用mysql为连接库

'connections' => [

 'mysql' => [
 'driver' => 'mysql',
 'host' => '192.168.0.xx',
 'database' => 'database',
 'username' => 'root',
 'password' => '',
 'charset' => 'utf8',
 'collation' => 'utf8_unicode_ci',
 'prefix' => 'tb_',
 'strict' => false,
 ],

 'mysql_snapshot' => [
 'driver' => 'mysql',
 'host' => env('DB_HOST_SNAPSHOT', '192.168.0.xx'),
 'database' => env('DB_DATABASE_SNAPSHOT', 'snapshot'),
 'username' => env('DB_USERNAME_SNAPSHOT', 'root'),
 'password' => env('DB_PASSWORD_SNAPSHOT', ''),
 'charset' => 'utf8',
 'collation' => 'utf8_unicode_ci',
 'prefix' => 'tb_',
 'strict' => false,
 ],
 ],

在某个需求中，需要使用子查询获取snapshot快照表库的关联数据，从而实现以下sql逻辑

SELECT ... From
 (SELECT
 sum(game_count) AS sum_count,
 max(game_count) AS max_count,
 game_room_id,
 record_date
 FROM
 `tb_xx_snapshot`
 WHERE
 record_date BETWEEN '2017-05-17' AND '2017-05-23'
 AND 
 type = '1'
 GROUP BY 
 game_room_id) as main
INNER JOIN `tb_xx_snapshot` AS `tb_gg` ON tb_gg.game_count = main.max_count and tb_gg.game_room_id = main.game_room_id
where
 tb_gg.record_date BETWEEN '2017-05-17' AND '2017-05-23'
AND 
 tb_gg.type = '1'
GROUP BY 
 tb_gg.game_room_id;

其中子查询主要用到以下query builder语句

$query = DB::table('xx_snapshot')->where('xx','yy')->groupBy('xx');
$main = DB::connection('mysql_snapshot')
 ->table(DB::raw("({$query->toSql()}) as tb_main"))
 ->mergeBindings($query->getQuery()) // 绑定参数，否则sql语句会只有'?'
 ->get();

而join语句中可传入匿名函数重新构造，如再其中加多几个连接条件，或者查询条件

$con = DB::table('xx_snapshot')
 ->join('xx_snapshot as gg', function ($query) {
 $query->on('gg.game_count', '=', 'xx_snapshot.max_count')
 ->on('gg.game_room_id', '=', 'xx_snapshot.game_room_id')
 ->where('gg.xx','123';
 })

实现上述需求完整代码如下：

$subQuery= GameroomModel::select(DB::raw('sum(game_count) as sum_count,max(game_count) as max_count,record_date,game_room_id')) 
 ->whereBetween('record_date',[$beginDay,$endDay])
 ->where('type','1')
 ->groupBy('game_room_id');

$main = DB::connection('mysql_snapshot')
 ->table(DB::raw("({$subQuery->toSql()}) as tb_main"))
 ->mergeBindings($playerGame->getQuery())
 ->join('gameroom_snapshot as gg', function ($join) {
 $join->on('gg.game_count', '=', 'main.max_count')
 ->on('gg.game_room_id', '=', 'main.game_room_id');
 })
 - >select('main.max_count','main.sum_count','gg.record_date','main.game_room_id')
 ->whereBetween('gg.record_date',[$beginDay,$endDay])
 ->groupBy('main.game_room_id')
 ->get();

代码中子查询和外层都group by了一次，应该可以再优化一下.

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