mysql - 如何在计数查询中使用“AS”？

如何在计数查询中使用AS？
实际上，我想要json result的{ "count":"number" }结果。我不知道该叫什么？

public function firstHourTrades(){

    $user_id = Auth::user()->id;
    $data = DB::table('finaltrade')
        ->join('exchanges', 'finaltrade.exchange_id', '=', 'exchanges.id')

        ->where('finaltrade.user_id', $user_id)
        ->whereTime(DB::raw('IF(finaltrade.buy_datetime<finaltrade.sell_datetime, finaltrade.buy_datetime, finaltrade.sell_datetime) '), '>=', DB::raw('exchanges.start_time'))
        ->whereTime(DB::raw('IF(finaltrade.buy_datetime<finaltrade.sell_datetime, finaltrade.buy_datetime, finaltrade.sell_datetime) '), '<=', DB::raw("ADDTIME(exchanges.start_time, '1:00:00')"))
        ->count();

    return response()->json($data);
}

最佳答案

您还可以执行原始选择并手动分配别名：

$data = DB::table('finaltrade')
    ->select(DB::raw('count(*) as count'))
    ->join('exchanges', 'finaltrade.exchange_id', '=', 'exchanges.id')
    ->where('finaltrade.user_id', $user_id)
    ->whereTime(DB::raw('IF(finaltrade.buy_datetime<finaltrade.sell_datetime, finaltrade.buy_datetime, finaltrade.sell_datetime) '), '>=', DB::raw('exchanges.start_time'))
    ->whereTime(DB::raw('IF(finaltrade.buy_datetime<finaltrade.sell_datetime, finaltrade.buy_datetime, finaltrade.sell_datetime) '), '<=', DB::raw("ADDTIME(exchanges.start_time, '1:00:00')"))
    ->get();