Laravel Carbon在字符串错误时约会diffInDays（）

I need to find the difference between the two dates. Say i have 2017-02-01 - 2017-01-01. The number of days between the two days is the output

$formatted_dt1=Carbon::parse($a->date)->format('Y-m-d');
$formatted_dt2=Carbon::parse($c->dt)->format('Y-m-d');
$date_diff=$formatted_dt1->diffInDays($formatted_dt2);

If I give the above code I get the error as

FatalThrowableError in ReportsController.php line 67:
Call to a member function diffInDays() on string

Carbon format() function will convert to string so remove format('Y-m-d') like this:

$formatted_dt1=Carbon::parse($a->date);

$formatted_dt2=Carbon::parse($c->dt);

$date_diff=$formatted_dt1->diffInDays($formatted_dt2);

Hope you understand. You can see docs here.

Not tested but try this:

$formatted_dt1=Carbon::parse($a->date);
$formatted_dt2=Carbon::parse($c->dt);
$date_diff=$formatted_dt1->diffInDays($formatted_dt2);

You can do in this way,

$formatted_dt1=Carbon::parse($a->date);
$formatted_dt2=Carbon::parse($c->dt);
$date_diff=$formatted_dt1->diffInDays($formatted_dt2)->format('Y-m-d');

First get the difference from two dates and then format the date.

You can only use the diffInDays() function on a Carbon instance at before date format apply.

$formatted_dt1=Carbon::parse($a->date);
$formatted_dt2=Carbon::parse($c->dt);

Now you should be able to compare:

$date_diff=$formatted_dt1->diffInDays($formatted_dt2);

if you want to apply date format, try below for compare them:

$date_diff=$formatted_dt1->diffInDays($formatted_dt2)->format('Y-m-d');

Check this document for further detail.

You are having this problem because you stored your date as string in the database. You can perform diffInDays($updated_at) or diffInDays($created_at) on the original laravel's created_at and updated_at because Laravel already stores them as dates by default so, when you are fetching them from the database, laravel gives it to you as a carborn instance (try dd($created_at)).

To solve your problem, go to your model and use this to convert your date column to dates

protected $dates = [
'my_date',
'my_other_date'
]

Then, you can now do

$formatted_dt1=Carbon::parse($a->date)->format('Y-m-d');
$formatted_dt2=Carbon::parse($c->dt)->format('Y-m-d');
$date_diff=$formatted_dt1->diffInDays($formatted_dt2);

OR You can use

Carbon\Carbon::parse($formatted_dt1)->diffInDays()