Laravel Subquery Value From hasmany Relation Value - mysql

Question

I have a model
Logbook and a model
LogbookEntries
Logbook hasMany LogbookEntries and LogbookEntries belongsto Logbook (out of the scope of the question though). In my LogbookEntries I have two fields (plus others): start date and end_date. I want to show all LogbookEntries which the following date entry as an example.
ENTRY 1
start_date: 01 Mar 19
end_date: 05 Mar 19
ENTRY 2
start_date: 06 Mar 19
end_date: 12 Mar 19
ENTRY 3
start_date: 19 Jun 19
end_date: 22 Jun 19
If I say show all which have a follow-up date, then only Entry 3 will display. My issue is:
Logbook::whereHas('LogbookEntries', function($q) {
$q->where('start_date', <???.end_date + 1 day>)
})

Answer 1

This worked for me:
If I understand your question correctly then I think the easiest way to achieve this would be with the following:
Note the use of whereraw instead of where so that we can use direct
mySql code
Logbook::whereHas('LogbookEntries', function($q) {
$q->whereraw('date_format(date(end_date),"%Y-%m-%d") = date_format(date(start_date),"%Y-%m-%d") + interval 1 day')
})
I tested this on my system and it worked a charm. However, my timestamps were in the format Y-m-d HH:mm:ii so I needed the date_format to change them. You may not need this. Therefore, you may want to also try the following:
Logbook::whereHas('LogbookEntries', function($q) {
$q->whereraw('date(end_date) = date(start_date) + interval 1 day')
})
As this would be a lot tidier.
Basically what we are doing is getting entries where the end_date is the same as the start_date + 1 day. You were close but just not quite there.
My system so you can see it working:
Without the whereraw statement:
>>> Task::Select('start_date','end_date')->get();
=> Illuminate\Database\Eloquent\Collection {#3325
all: [
App\Task {#3307
start_date: "2018-12-20 08:00:00",
end_date: null,
},
App\Task {#3291
start_date: "2018-12-18 00:00:00",
end_date: "2018-12-19 00:00:00",
},
App\Task {#3318
start_date: "2018-12-19 00:00:00",
end_date: "2019-01-03 00:00:00",
},
App\Task {#3319
start_date: "2018-12-20 00:00:00",
end_date: "2018-12-21 00:00:00",
},
App\Task {#3310
start_date: "2018-12-20 00:00:00",
end_date: "2018-12-21 00:00:00",
},
App\Task {#3317
start_date: "2018-12-20 14:43:16",
end_date: "2018-12-21 14:43:16",
},
App\Task {#3316
start_date: "2018-12-20 14:45:27",
end_date: "2018-12-27 14:45:27",
},
App\Task {#3315
start_date: "2018-12-20 14:46:48",
end_date: "2018-12-24 14:46:48",
},
App\Task {#3313
start_date: "2018-12-21 09:25:24",
end_date: "2018-12-24 09:25:24",
},
App\Task {#3298
start_date: "2019-01-02 08:10:19",
end_date: "2019-01-16 08:10:19",
},
],
}
With the whereraw statement:
>>> Task::Select('start_date','end_date')->whereraw('date_format(date(end_date),"%Y-%m-%d") = date_format(date(start_dat
e),"%Y-%m-%d") + interval 1 day')->get();
=> Illuminate\Database\Eloquent\Collection {#3314
all: [
App\Task {#3312
start_date: "2018-12-18 00:00:00",
end_date: "2018-12-19 00:00:00",
},
App\Task {#3309
start_date: "2018-12-20 00:00:00",
end_date: "2018-12-21 00:00:00",
},
App\Task {#3320
start_date: "2018-12-20 00:00:00",
end_date: "2018-12-21 00:00:00",
},
App\Task {#3329
start_date: "2018-12-20 14:43:16",
end_date: "2018-12-21 14:43:16",
},
],
}