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  • laravel5.5中查询构造器的使用

    //查询构造器新增数据:
        public function query1()
        {
    
            /*        $bool=DB::table('student')->insert(
                        ['name'=>'小李','age'=>12]
                    );
                    var_dump($bool);*/
    
            //获取插入的id
            /*        $ids = DB::table('student')->insertGetId(
                        ['name' => 'php', 'age' => 22]
                    );
                    var_dump($ids);*/
    
            $bool = DB::table('student')->insert([
                    ['name' => '小李001', 'age' => 12],
                    ['name' => '小李002', 'age' => 121]
                ]
            );
            var_dump($bool);
    
        }
    
        //查询构造器更新数据:
        public function query2()
        {
            /*      $num=DB::table('student')
                      ->where('id',1004)
                      ->update(['age'=>101]);
                  var_dump($num);*/
    
            //自增1
            /* $num=DB::table('student')->increment('age');*/
    //自增3
            /* $num=DB::table('student')->increment('age',3);*/
    
            //自减1
            /*$num=DB::table('student')->decrement('age');*/
    
            //自减3
            /*  $num=DB::table('student')->increment('age',3);
              var_dump($num);*/
    
            //带条件自减
            /*        $num=DB::table('student')
                        ->where('id',1004)
                        ->decrement('age',3);
                    var_dump($num);*/
    
            $num = DB::table('student')
                ->where('id', 1004)
                ->increment('age', 3, ['name' => '小王']);
            var_dump($num);
        }
    
        //使用查询构造器删除数据:
        public function query3()
        {
            /*        $num=DB::table('student')
                        ->where('id','>=',1008)
                        ->delete();
                    var_dump($num);*/
    
            //清空数据表
            DB::table('student')->truncate();
        }
    
        //使用查询构造器查询数据:
        public function query4()
        {
            /*        $num=DB::table('student')->insert([
                        ['id'=>1001,'name'=>'name1','age'=>18],
                        ['id'=>1002,'name'=>'name2','age'=>19],
                        ['id'=>1003,'name'=>'name3','age'=>28],
                        ['id'=>1004,'name'=>'name4','age'=>38],
                        ['id'=>1005,'name'=>'name5','age'=>78]
                    ]);
                    var_dump($num);*/
    
            //get(); 获取表中所有数据
            /*        $students=DB::table('student')->get();
                    dd($students);*/
    
            //first() 获取第一条数据:
            /*$students=DB::table('student')
                ->orderBy('id','desc')
                ->first();
            dd($students);*/
    
            //where查询数据:
            /*$students=DB::table('student')
                ->where('id','>=',1002)
                ->get();
            dd($students);*/
    
            //加多个条件进行查询
            /*$students=DB::table('student')
                ->whereRaw('id>=? and age>?',[1003,38])
                ->get();
            dd($students);*/
    
            //pluck()
            /*$names=DB::table('student')
                ->pluck('name');
            dd($names);*/
    
            //lists 5.3之后已经弃用
            /*        $names=DB::table('student')
                        ->lists('name','id');
                    dd($names);*/
    
            //select() 指定查找:
            /*$students=DB::table('student')
                ->select('id','name','age')->get();
            dd($students);*/
    
            //chunk:
            echo '<pre>';
            $students = DB::table('student')
                ->orderBy('id', 'asc')
                ->chunk(2, function ($students) {
                    var_dump($students);
                    return false; //查询出一组数据出来:
                });
        }
    
        //查询构造器中的聚合函数:
        public function query5()
        {
            //count() 统计数据数量
            /*$num=$num=DB::table('student')->count();
            var_dump($num);*/
    
            /*$max=$num=DB::table('student')->max('age');
            var_dump($max);*/
    
            /*$min=$num=DB::table('student')->max('age');
            var_dump($min);*/
    
            /*$avg=$num=DB::table('student')->avg('age');
            var_dump($avg);*/
    
            $sum = $num = DB::table('student')->sum('age');
            var_dump($sum);
        }
    

      

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  • 原文地址:https://www.cnblogs.com/yiweiyihang/p/7826243.html
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