php 如何在 Laravel 中使用 increment() 和 decrement()

how to use increment() and decrement() in laravel

提问by cnbwd

I have a table total_count

我有一张桌子 total_count

+----+--------+-------+------+---------+---------+---------+
| id | studid | month | year | acls_id | total_p | total_a |
+----+--------+-------+------+---------+---------+---------+
| 1  |   30   |  08   | 2015 |   12    |    5    |    2    |
| 2  |   35   |  08   | 2015 |   12    |    5    |    2    |
| 3  |   52   |  08   | 2015 |   12    |    5    |    2    |
| 4  |   53   |  08   | 2015 |   12    |    5    |    2    |
| 5  |   54   |  08   | 2015 |   12    |    5    |    2    |
| 6  |   55   |  08   | 2015 |   12    |    5    |    2    |
| 7  |   30   |  09   | 2015 |   12    |    3    |    0    |
| 8  |   35   |  09   | 2015 |   12    |    3    |    0    |
| 9  |   52   |  09   | 2015 |   12    |    2    |    1    |
| 10 |   53   |  09   | 2015 |   12    |    3    |    0    |
| 11 |   54   |  09   | 2015 |   12    |    3    |    0    |
| 12 |   55   |  09   | 2015 |   12    |    3    |    0    |
+----+--------+-------+------+---------+---------+---------+

I want to increment and decrement for each student total_pand total_a.

我想递增和递减为每个学生total_p和total_a。

when i am edit my student attendance list.

当我编辑我的学生出勤表时。

eg:studid 30 total_p = 5 and total_a= 2 ,so iam edit my attendance present become absent .

例如：studid 30 total_p = 5 和 total_a= 2 ，所以我编辑我的出席现在变得缺席。

so want decrement total_p by 1 and increment total_a by 1.

所以想要将 total_p 减少 1 并将 total_a 增加 1。

So I'd like to get the total of each month for each studidand a increment and decrement of total_pand total_afor the total months.

所以我想以获得每个总每个月的studid和的增量和减量 total_p和total_a总个月。

My controllercode is

我的控制器代码是

foreach ($student as $student) {
            if ($present == 0) {
                $query = DB::table($wys_total_attend_table)
                    ->where('studid', $student->id)
                    ->where('smonth', '=', $date_exploded[1])
                    ->where('syear', '=', $date_exploded[2])
                    ->update([
                        'stotal_p' => DB::raw('stotal_p - 1'),
                        'stotal_a' => DB::raw('stotal_a + 1'),
                    ]);
            } elseif ($present == 1) {
                $query = DB::table($wys_total_attend_table)
                    ->where('studid', $student->id)
                    ->where('smonth', '=', $date_exploded[1])
                    ->where('syear', '=', $date_exploded[2])
                    ->update([
                        'stotal_p' => DB::raw('stotal_p + 1'),
                        'stotal_a' => DB::raw('stotal_a - 1'),
                    ]);
            }
        }

but it doesn't work..

但它不起作用..

How to use increment()and decrement()in query builder format?

如何使用increment()和decrement()查询构建器格式？

for eg:if i only edit studid = 30 attendance increment total_p value 1 and (present == 1) studid = 30 total_p = 6 and total_a = 1 and other studid values are old value.

例如：如果我只编辑studid = 30 出勤增量total_p 值1 和（present == 1）studid = 30 total_p = 6 和total_a = 1 并且其他studid 值是旧值。

回答by jedrzej.kurylo

increment()and decrement()do not return a Query Builderobject, so you cannot chain your calls like you do in your code:

increment()和decrement()不返回查询生成器对象，因此您不能像在代码中那样链接调用：

->increment('stotal_p', 1)->decrement('stotal_a', 1); 

You'll need to call each method separately. Moreover, 1is the default value for the increment/decrement, so no need to pass it.

您需要分别调用每个方法。此外，1是increment/decrement的默认值，因此无需传递它。

This should do the trick:

这应该可以解决问题：

$query = DB::table($wys_total_attend_table)
  ->where('studid',$student->id)                                     
  ->where('smonth','=',$date_exploded[1])
  ->where('syear','=',$date_exploded[2]);

$query->increment('stotal_a');
$query->decrement('stotal_p');

回答by Aamer Shahzad

From Laravel 5.7+ you can increment or decrement the given column by using increment()or decrement()methods without writing the manual update statement.

从 Laravel 5.7+ 开始，您可以使用increment()或decrement()方法增加或减少给定的列，而无需编写手动更新语句。

Laravel Doc & Example

Laravel 文档和示例

https://laravel.com/docs/5.8/queries#increment-and-decrement

https://laravel.com/docs/5.8/queries#increment-and-decrement

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

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

Get the Student Attendance

获取学生出勤率

$studentAtd = DB::table($wys_total_attend_table)
  ->where('studid',$student->id)                                     
  ->where('smonth','=',$date_exploded[1])
  ->where('syear','=',$date_exploded[2]);

Increment or Decrement Attendance column

增加或减少出勤栏

$studentAtd->increment('stotal_a');
$studentAtd-> decrement('stotal_p');