这篇文章给大家分享的是有关laravel中子查询&join的使用案例的内容。小编觉得挺实用的，因此分享给大家做个参考，一起跟随小编过来看看吧。
本项目中关联了2个数据库
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'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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