我解释了 cmets 中的所有步骤,但我也会在这里解释。
当您遍历每一行时,您首先需要获取number 字段为1、2 或3 的所有行,无论当前迭代中的数字是多少。
在这种情况下,第一个循环结果将是:
number date amount
1 2020-01-01 10
1 2020-01-01 -5
1 2020-01-01 -5
然后将amount 列中的值相加(相加)。
在这种情况下,它的总和是这样的:
10
-5
-5
-----
0
如果答案是不是 0,请取出当前工作表 ($sheet) 并返回您当前拥有的内容,以便导出。
全班:
...
use Maatwebsite\Excel\Concerns\FromArray;
class ExampleExport implements FromArray
{
public function array() : array
{
// EXAMPLE hardcoded data for the purpose of this demo
$rows = [
[
'number' => 1,
'date' => '2020-01-01',
'amount' => 10
],
[
'number' => 1,
'date' => '2020-01-01',
'amount' => -5
],
[
'number' => 1,
'date' => '2020-01-01',
'amount' => -5
],
[
'number' => 2,
'date' => '2020-02-02',
'amount' => 20
],
[
'number' => 2,
'date' => '2020-02-02',
'amount' => -20 // <-------- Change this to -21 to test
],
[
'number' => 3,
'date' => '2020-03-03',
'amount' => 50
],
[
'number' => 3,
'date' => '2020-03-03',
'amount' => -50
],
[
'number' => 3,
'date' => '2020-03-03',
'amount' => 40
],
[
'number' => 3,
'date' => '2020-03-03',
'amount' => -40
],
];
// EXAMPLE hardcoded data for the purpose of this demo
$rows = collect($rows);
// You probably going to get this from your database so should look like this:
// $rows = \App\Model::all(['number', 'date', 'amount']); // OR below
// $rows = DB::table('examples')->select(['number', 'date', 'amount'])->get();
// Blank sheet
$sheet = [];
foreach ($rows as $row) {
// Get all the rows where the `number` field has the same value,
// for example 1, 2, or 3, then sum the `amount` field (add up).
//
// If the amount does not add up to 0, stop and return what you currently got
if ($rows->where('number', $row['number'])->sum('amount') !== 0) {
return $sheet;
}
// Else, add them to the sheet and continue.
$sheet[] = $row;
}
return $sheet;
}
}
结果:
当amount 加起来等于0:
当amount 不等于0: