1.查詢結果集

<?php

namespace App\Http\Controllers;

use DB;
use App\Http\Controllers\Controller;

class UserController extends Controller
{
    /**
     * Show a list of all of the application's users.
     *
     * @return Response
     */
    public function index()
    {
        $users = DB::table('users')->get();

        return view('user.index', ['users' => $users]);
    }
}

只查詢一個結果

$user = DB::table('users')->where('name', 'John')->first();
echo $user->name;

如果不需要整行數據，而是其中的一個

$email = DB::table('users')->where('name', 'John')->value('email');

如果面對成千上萬條數據，不可能一次讀取，需要用到chunk函數

DB::table('users')->chunk(100, function($users) {
    foreach ($users as $user) {
        //
    }
});
//返回false停止
DB::table('users')->chunk(100, function($users) {
    // Process the records...

    return false;
});

查詢列的數據

$titles = DB::table('roles')->lists('title');

foreach ($titles as $title) {
    echo $title;
}
//多列數據
$roles = DB::table('roles')->lists('title', 'name');

foreach ($roles as $name => $title) {
    echo $title;
}

count, max,min, avg, and sum

$users = DB::table('users')->count();
$price = DB::table('orders')->max('price');
$price = DB::table('orders')
                ->where('finalized', 1)
                ->avg('price');

2.[Selects]

$users = DB::table('users')->select('name', 'email as user_email')->get();
//返回不同的值
$users = DB::table('users')->distinct()->get();
//如果想為一個已有的查詢語句添加列
$query = DB::table('users')->select('name');
$users = $query->addSelect('age')->get();

原生查詢

$users = DB::table('users')
                     ->select(DB::raw('count(*) as user_count, status'))
                     ->where('status', '<>', 1)
                     ->groupBy('status')
                     ->get();

3.Join

Inner Join

$users = DB::table('users')
            ->join('contacts', 'users.id', '=', 'contacts.user_id')
            ->join('orders', 'users.id', '=', 'orders.user_id')
            ->select('users.*', 'contacts.phone', 'orders.price')
            ->get();

Left Join

$users = DB::table('users')
            ->leftJoin('posts', 'users.id', '=', 'posts.user_id')
            ->get();

高級 Join

DB::table('users')
        ->join('contacts', function ($join) {
            $join->on('users.id', '=', 'contacts.user_id')->orOn(...);
        })
        ->get();

where 語句orWhere

DB::table('users')
        ->join('contacts', function ($join) {
            $join->on('users.id', '=', 'contacts.user_id')
                 ->where('contacts.user_id', '>', 5);
        })
        ->get();

4.Union

UNION組合兩個表時，將重復的記錄刪除；而使用UNION ALL組合兩多個表時，不考慮結果集中是否存在重復記錄，包括重復行

$first = DB::table('users')
            ->whereNull('first_name');

$users = DB::table('users')
            ->whereNull('last_name')
            ->union($first)
            ->get();

5.where 語句

$users = DB::table('users')->where('votes', '=', 100)->get();
//===
$users = DB::table('users')->where('votes', 100)->get();

orWhere

$users = DB::table('users')
                    ->where('votes', '>', 100)
                    ->orWhere('name', 'John')
                    ->get();

****whereNotBetween****

$users = DB::table('users')
                    ->whereNotBetween('votes', [1, 100])
                    ->get();

whereIn / whereNotIn

$users = DB::table('users')
                    ->whereIn('id', [1, 2, 3])
                    ->get();

whereNull / whereNotNull

$users = DB::table('users')
                    ->whereNull('updated_at')
                    ->get();

4.高級where的查詢

DB::table('users')
            ->where('name', '=', 'John')
            ->orWhere(function ($query) {
                $query->where('votes', '>', 100)
                      ->where('title', '<>', 'Admin');
            })
            ->get();
==>
select * from users where name = 'John' or (votes > 100 and title <> 'Admin')

Exists Statements

DB::table('users')
            ->whereExists(function ($query) {
                $query->select(DB::raw(1))
                      ->from('orders')
                      ->whereRaw('orders.user_id = users.id');
            })
            ->get();
==>
select * from users
where exists (
    select 1 from orders where orders.user_id = users.id
)

6.[Ordering, Grouping, Limit, & Offset]

orderBy

$users = DB::table('users')
                ->orderBy('name', 'desc')
                ->get();

groupBy / having / havingRaw

$users = DB::table('users')
                ->groupBy('account_id')
                ->having('account_id', '>', 100)
                ->get();

$users = DB::table('orders')
                ->select('department', DB::raw('SUM(price) as total_sales'))
                ->groupBy('department')
                ->havingRaw('SUM(price) > 2500')
                ->get();

skip / take
可以用于分頁

$users = DB::table('users')->skip(10)->take(5)->get();

7.[Inserts]

DB::table('users')->insert(
    ['email' => 'john@example.com', 'votes' => 0]
);

一次插入多個

DB::table('users')->insert([
    ['email' => 'taylor@example.com', 'votes' => 0],
    ['email' => 'dayle@example.com', 'votes' => 0]
]);

對于有自增id的表

$id = DB::table('users')->insertGetId(
    ['email' => 'john@example.com', 'votes' => 0]
);

8.[Updates]

DB::table('users')
            ->where('id', 1)
            ->update(['votes' => 1]);

增加與減少

DB::table('users')->increment('votes');

DB::table('users')->increment('votes', 5);

DB::table('users')->decrement('votes');

DB::table('users')->decrement('votes', 5);

可以指定其余列用于跟新

DB::table('users')->increment('votes', 1, ['name' => 'John']);

9.[Deletes]

DB::table('users')->where('votes', '<', 100)->delete();

如果想刪除真個表內容，并且重置id

DB::table('users')->truncate();

10.鎖

sharedLock
讀鎖，跟新的時候不能查詢

DB::table('users')->where('votes', '>', 100)->sharedLock()->get();

lockForUpdate
寫鎖，阻止其它shared lock查詢和跟新

DB::table('users')->where('votes', '>', 100)->lockForUpdate()->get();