Laravel 联合和分页

识别问题

您收到的错误是由于您的UNION语句中的两个查询没有相同的列数.当使用UNION或UNION ALL时，您必须确保这两个SELECT语句具有相同的列数，并且这些列也应该是类似的数据类型.

解释

看起来您正在try 将四个表联接在一起:WARESTORIES、WAREARY_PICKINGS、WARRAINE_ISLES、WARRAINS_RACKS和WAREARY_BINS.每个子查询中的SELECT条语句也应该具有相同的列数.但是在您的例子中，第二个子查询 Select 了9列，而第一个子查询只 Select 了3列.

解

您应该在第一个查询中添加缺少的列，并用NULL填充它们，以便它与第二个查询中的列相匹配.这样，您就是在欺骗系统，使其认为这两个子查询具有相同的 struct .

以下是如何实现这一点的方法:

$pickings = Warehouse::where('warehouses.id', $id)
            ->leftJoin('warehouse_pickings as wp', 'wp.warehouse_id', '=', 'warehouses.id')
            ->groupBy('wp.id')
            ->select(
                DB::raw('null as warehouse_id'),
                DB::raw('null as warehouse_name'),
                DB::raw('null as wi_id'),
                DB::raw('null as wi_type'),
                DB::raw('null as wi_name'),
                DB::raw('null as wr_id'),
                DB::raw('null as wr_name'),
                DB::raw('null as wb_id'),
                DB::raw('null as wb_name'),
                'wp.id as wp_id',
                'wp.type as wp_type',
                'wp.location as wp_location',
            );

$config = Warehouse::leftjoin('warehouse_isles as wi', 'wi.warehouse_id', '=', 'warehouses.id')
            ->leftjoin('warehouse_racks as wr', 'wr.warehouse_isle_id', '=', 'wi.id')
            ->leftJoin('warehouse_bins as wb', 'wb.warehouse_rack_id', '=', 'wr.id')
            ->where('warehouses.id', $id)
            ->groupBy('wb.id', 'wr.id', 'wi.id')
            ->select(
                'warehouses.id  as warehouse_id',
                'warehouses.name  as warehouse_name',
                'wi.id as wi_id',
                'wi.type as wi_type',
                'wi.name as wi_name',
                'wr.id as wr_id',
                'wr.name as wr_name',
                'wb.id as wb_id',
                'wb.name as wb_name',
                DB::raw('null as wp_id'),
                DB::raw('null as wp_type'),
                DB::raw('null as wp_location')
            );

$query = $config->unionAll($pickings);
return $query->paginate(5);