商店最大的子值

Question

$exmp = DB::table('cr_tblcomplaintregistration') 
      ->select(DB::raw('MAX(CAST(SUBSTRING(complaintRegNo,16,length(complaintRegNo))+1 AS int))'))->first(); 
     dd($exmp); 

我得到：

{#337 ▼ 
    +"MAX(CAST(SUBSTRING(complaintRegNo,16,length(complaintRegNo))+1 AS int))": 51 
} 

如何存放在另一個變量只值51？

Answer 1

我假設問題是可擴展名稱？如果你想$exmp是列值

->select(
DB::raw('MAX(CAST(SUBSTRING(complaintRegNo,16,length(complaintRegNo))+1 AS int)) AS maximum') 
) 

，只是屬性添加到您的鏈的末端：如果是這樣，你可以添加一個SQL別名

$exmp = DB::table('cr_tblcomplaintregistration') 
->select(DB::raw('MAX(CAST(SUBSTRING(complaintRegNo,16,length(complaintRegNo))+1 AS int)) as maximum')) 
->first() 
->maximum; 

當然，你可能想要得到如果first()之前不是空的。