时间戳

首页 > 解决方案 > 如何从表中获取所有行，与数据透视表连接是否有关系？

laravel - 如何从表中获取所有行，与数据透视表连接是否有关系？

问题描述

我将 Laravel 用于服务器端并定义了模型的所有关系。

我有如下表结构

table_A
id | title
1  | apple
2  | banana

table_B
id | A_id | C_id
1  | 1    | 1
2  | 1    | 2
3  | 2    | 2


table_C
id | title
1  | green
2  | red
3  | black

输出现在我想要 table_A 中的所有行以及 table_A 行对象中 table_C 中的所有行，如果 A_id 和 C_id 匹配，则将数据保存在 table_C 对象中，否则为空

例子

[
    0 : {
        id      :   1,
        title   :   'apple',
        table_C : [
            0 : {
                id      :   1
                title   :   green
                table_B : {
                        id   :  1,
                        A_id :  1,
                        B_id :  1
                } 
            },
            1 : {
                id      :   2
                title   :   red
                table_B : {
                        id   :  2,
                        A_id :  1,
                        B_id :  2
                } 
            },
            2 : {
                id      :   3
                title   :   black
                table_B :   null 
            }
        ]

    },
    1 : {
        id      :   1,
        title   :   'banana',
        table_C : [
            0 : {
                id      :   1
                title   :   green
                table_B :   null 
            },
            1 : {
                id      :   2
                title   :   red
                table_B : {
                        id   :  3,
                        A_id :  2,
                        B_id :  2
                } 
            },
            2 : {
                id      :   3
                title   :   black
                table_B :   null 
            }
        ]

    }
]

我还定义了 laravel 关系，请指导我更好的方法来跟踪输出。

标签： laravel

解决方案

它不会产生确切的结果..

    $res = [];
    $t1 = DB::table('tableA')->get();
    $t3 = DB::table('tableC')->get();
    $t2 = DB::table('tableB')->get();
    $key = 0;
    foreach($t1 as  $table1)
    { 
        foreach($t3 as $ke => $table)
        {

            foreach($t2 as $table2)
            {
                if($table2->A_id == $table1->id && $table2->C_id == $table->id)
                {
                    $res[$key]['id'] = $table1->id;
                    $res[$key]['title'] = $table1->title;
                    $res[$key]['table_c']['id'] = $table->id;
                    $res[$key]['table_c']['title'] = $table->title;
                    $res[$key]['table_c']['table_b']['id'] = $table2->id;
                    $res[$key]['table_c']['table_b']['A_id'] = $table1->id;
                    $res[$key]['table_c']['table_b']['C_id'] = $table->id;                        
                }    
                else
                {
                    $res[$key]['id'] = $table1->id;
                    $res[$key]['title'] = $table1->title;
                    $res[$key]['table_c']['id'] = $table->id;
                    $res[$key]['table_c']['title'] = $table->title;

                }

            }
            $key++;
            reset($table2);

        }
        reset($table);
    }
    dd($res);

输出将是

 array:6 [▼
 0 => array:3 [▼
"id" => 1
"title" => "apple"
"table_c" => array:3 [▼
  "id" => 1
  "title" => "green"
  "table_b" => array:3 [▼
    "id" => 1
    "A_id" => 1
    "C_id" => 1
  ]
]
]
1 => array:3 [▼
"id" => 1
"title" => "apple"
"table_c" => array:3 [▼
  "id" => 2
  "title" => "red"
  "table_b" => array:3 [▼
    "id" => 2
    "A_id" => 1
    "C_id" => 2
  ]
]
]
2 => array:3 [▼
"id" => 1
"title" => "apple"
"table_c" => array:2 [▼
  "id" => 3
  "title" => "black"
]
]
3 => array:3 [▼
"id" => 2
"title" => "banana"
"table_c" => array:2 [▼
  "id" => 1
  "title" => "green"
]
]
4 => array:3 [▼
"id" => 2
"title" => "banana"
"table_c" => array:3 [▼
  "id" => 2
  "title" => "red"
  "table_b" => array:3 [▼
    "id" => 3
    "A_id" => 2
    "C_id" => 2
  ]
]
]
5 => array:3 [▼
"id" => 2
"title" => "banana"
"table_c" => array:2 [▼
  "id" => 3
  "title" => "black"
]
]
]

推荐阅读