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数据库访问类链式查询方法
王佳祥
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数据库访问类链式查询方法

一、查询构造器

1.first()：查询一条记录

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     public function chain(){
  9.         //链式调用
  10.         $res2 = DB::table('staff')->where('id',1002)->first(['id','name']);
  11.         echo '<pre>';
  12.         print_r($res2);
  13.     }
  14. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/chain','Home@chain');

2.get():查询多条记录

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //查询多条记录
  9.     public function lists(){
  10.         $res = DB::table('staff')->where('sex',2)->get();
  11.         $data = $res->toArray();
  12.         echo '<pre>';
  13.         print_r($res);
  14.         echo '<hr>';
  15.         print_r($data);
  16.     }
  17. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/list','Home@lists');

3.value():查询某一列的当前值

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //查询某一列的当前值
  9.     Public function val(){
  10.         $res = DB::table('staff')->where('id',1002)->first(['name']);
  11.         $res2 = DB::table('staff')->where('id',1002)->value('name');
  12.         echo '<pre>';
  13.         print_r($res);
  14.         print_r($res2);
  15.     }
  16. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/val','Home@val');

  • first() 返回对象的键和值

  • value()返回值

4.piuck():返回指定字段组成的集合

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //pluck():返回指定字段组成的集合
  9.     public function pluck(){
  10.         $res = DB::table('staff')->pluck('name');
  11.         $res2 = DB::table('staff')->get('name');
  12.         $res3 = DB::table('staff')->pluck('name','id');
  13.         echo '<pre>';
  14.     print_r($res);
  15.     print_r($res2);
  16.     print_r($res3);
  17.     }
  18. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/pluck','Home@pluck');

  • pluck(value) ： 返回指定key的值组成的集合

  • pluck(value, key) : 返回指定value,key的值组成的集合

二、链式操作的增删改查

1.新增操作：insert()

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //新增记录
  9.     public function insert2(){
  10.         $data = [
  11.             ["name"=>"诸葛亮","sex"=>1,"age"=>40,"hiredate"=>"2020-09-17"],
  12.             ["name"=>"貂蝉","sex"=>0,"age"=>28,"hiredate"=>"2020-09-17"],
  13.             ["name"=>"吕布","sex"=>1,"age"=>33,"hiredate"=>"2020-09-17"],
  14.             ["name"=>"西施","sex"=>0,"age"=>30,"hiredate"=>"2020-09-17"],
  15.         ];
  16.         $res = DB::table('staff')->insert($data);
  17.         var_dump($res);
  18.     }
  19. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/insert2','Home@insert2');

1.更新操作：update()

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //更新记录
  9.     public function update2(){
  10.         $res = DB::table('staff')->where('sex',1)->update(['sex'=>2]);
  11.         var_dump($res);
  12.     }
  13. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/update2','Home@update2');

3.删除操作：delete()

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //删除记录
  9.     public function delete2(){
  10.         $res = DB::table('staff')->where('id',1048)->delete();
  11.         var_dump($res);
  12.     }
  13. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/delete2','Home@delete2');

三、聚合查询

1.max():最大值

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //聚合查询
  9. public function juhe(){
  10.     //最大值
  11.    $res = DB::table('staff')->max('salary');
  12.    var_dump($res);
  13.     }
  14. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/juhe','Home@juhe');

2.min():最小值

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //聚合查询
  9. public function juhe(){
  10.     //最小值
  11.    $res = DB::table('staff')->min('salary');
  12.    var_dump($res);
  13.     }
  14. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/juhe','Home@juhe');

3.avg():平均值(所有记录的平均值)

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //聚合查询
  9. public function juhe(){
  10.     //平均值
  11.    $res = DB::table('staff')->avg('salary');
  12.    var_dump($res);
  13.     }
  14. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/juhe','Home@juhe');

4.sum():求和

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //聚合查询
  9. public function juhe(){
  10.     //求和
  11.    $res = DB::table('staff')->sum('salary');
  12.    var_dump($res);
  13.     }
  14. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/juhe','Home@juhe');

5.count():统计记录条数

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     //聚合查询
  9. public function juhe(){
  10.    //count统计记录
  11.    $res = DB::table('staff')->count('salary');
  12.    var_dump($res);
  13.     }
  14. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/juhe','Home@juhe');

6.as:临时别名

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     public function select(){
  9.         $res = DB::table('staff')->select('id','name as username','age as userage')->get();
  10.         echo '<pre>';
  11.         print_r($res);
  12.         }
  13. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/select','Home@select');

7.dump()打印输出结果,执行完继续执行下面的代码（只做调试用）

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     public function select(){
  9.         $res = DB::table('staff')->select('id','name as username','age as userage')->get();
  10.         dump($res);
  11.         echo '<h1>继续执行</h1>';
  12.         }
  13. }

8.dd()执行完直接终止，不再执行下面的代码（只做调试用）

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     public function select(){
  9.         $res = DB::table('staff')->select('id','name as username','age as userage')->get();
  10.         dd($res);
  11.         echo '<h1>继续执行</h1>';
  12.         }
  13. }

9.where():多条件查询

控制器：Home.php

  1. <?php
  2. namespace App\Http\Controllers;
  3. use Illuminate\Http\Request;
  4. use Illuminate\Support\Facades\DB;
  6. Class Home extends Controller{
  7.     //链式操作
  8.     public function where(){
  9.         $res = DB::table('staff')->where('age','<',30)->where('salary','<',10000)->get();
  10.         echo '<pre>';
  11.         print_r($res);
  12.     }
  13. }

路由：web.php

  1. <?php
  2. use Illuminate\Support\Facades\Route;
  3. Route::get('/home/where','Home@where');

批改老师：天蓬老师天蓬老师

批改状态：合格

老师批语：坚持到现在不容易,继续
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