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 
} 

如何存放在另一个变量只值51？

Answer 1

我假设问题是可扩展名称？如果你想$exmp是列值

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

，只是属性添加到您的链的末端：如果是这样，你可以添加一个SQL别名

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

当然，你可能想要得到如果first()之前不是空的。