I am trying to get the value of a single column using Eloquent:
MyModel::where('field', 'foo')->get(['id']); // returns [{"id":1}]
MyModel::where('field', 'foo')->select('id')->first() // returns {"id":1}
However, I am getting anything but the value 1. How can get that 1?
NOTE: It is possible that the record with field of foo does not exist in the table!
EDIT
I am ideally looking for a single statement that either returns the value (e.g. 1) or fails with a '' or null or other. To give you some more context, this is actually used in Validator::make in one of the rules:
'input' => 'exists:table,some_field,id,' . my_query_above...
EDIT 2
Using Adiasz's answer, I found that MyModel::where('field', 'foo')->value('id') does exactly what I need: returns an integer value or an empty string (when failed).
Laravel is intuitive framework... if you want value just call value() method.
MyModel::find(PK)->value('id');
MyModel::where('field', 'foo')->first()->value('id');
You're using the Eloquent query builder, so by default, it'll return an Eloquent model with only the value you wish.
The method you're looking for is pluck() which exists in the normal query builder (of which the Eloquent one extends) so your code should look as follows:
MyModel::where('field', 'foo')->pluck('id'); // returns [1]
The value() method that is being used in the other answers is an Eloquent model method. Using that means that the framework queries the database, hydrates the model and then returns only that value. You can save yourself a few keystrokes and few CPU cycles by using pluck() and have it handled simply in one query.
Related
I am using laravel
I want to change the value of a column according to a specific condition.
if a condition is satisfied in wherehas then change the value of specific column to 1 let's say.How could i do it.
if i can call a function in the model inside the wherehas function to change the value how could I do it ??
i can iterate the result set using a 2 for loops and change it, however I want to decrease the complexity by changing the value while retrieving the data
Course::with('stages','stages.levels')->whereHas('stages.levels', function($query)use ($levelsarray){
$query->wherenotIn('id', $levelsarray);
here I want to change a column value in table levels
})->first();
Here is a general way,
Assuming you have Three models, Course, Stage, Level
When you are retrieving data from Level model, add an accessor,
For more info click here.
Eg:
On Level.php model,
public function getColumnNameAttribute($value) // replace ColumnName with column name
{
//write application logic here.
return $value;
}
How I can query using Laravel Eloquent the following:
->where('items.type',"shirt")
->where('items.type',"glass")
I need to get the items with the type of shirt and glass
The above works with 1 Where on the same column. If I place the 2nd Where (glass), nothing is returned.
My desired query, as SQL:
WHERE items.type == "shirt" || items.type == "gass"
Use the orWhere method.
->where('items.type', 'shirt')->orWhere('items.type', 'glass')
It's documented on https://laravel.com/docs/5.2/queries#where-clauses.
You may chain where constraints together, as well as add or clauses to the query. The orWhere method accepts the same arguments as the where method:
You can also use the whereIn method.
->whereIn('items.type', ['shirt', 'glass'])
The whereIn method verifies that a given column's value is contained within the given array:
If you want a OR condition, you should wrap it within a where!
->where(function($query){
$query->where('items.type',"shirt")->whereOr('items.type',"glass");
});
OR
->whereIn('items.type', ['shirt', 'glass'])
I want to get alternative products pictures.
dd($alternativeProduct->pictures);
When die and dump i get this result.
I need to get only the picture which is main. If main equals to 1. It is main picture.
When I write
dd($alternativeProduct->pictures->where('main', 1))
I got an empty array.
Here is my relation with Product and Picture relation
public function pictures(){
return $this->hasMany('App\Models\ProductPicture');
}
What can i do ?
The where method in a collection has three parameters: $key, $value and $strict, the last one defaults to true if not passed when calling the method. When $strict is true the comparison is done via === which does not do type coercion, meaning "1" === 1 is false.
From your dump data, I can see that "main" => "1" which means it's a string and you're passing an integer 1 to the where method, resulting in what I described above as a false condition and returning an empty result set. You can fix that by disabling strict comparison:
$alternativeProduct->pictures->where('main', 1, false);
// or the equivalent helper whereLoose
$alternativeProduct->pictures->whereLoose('main', 1);
Or passing a string as the value:
$alternativeProduct->pictures->where('main', "1");
That being said, if that's the only place you're using that collection in that request's context, I suggest that you filter the results at the database level, not after they are fetched, like so:
$alternativeProduct->pictures()->where('main', 1)->get();
Accessing the relations as a method ->pictures(), instead of as a property ->pictures, will return a Query Builder instance that allows you to add conditions to the database query and only fetch the actual items you need from the database, instead of fetching them all and filtering them out afterwards.
You may want to use whereLoose instead:
dd($alternativeProduct->pictures->whereLoose('main', 1))
From the Laravel docs:
The where method uses strict comparisons when checking item values. Use the whereLoose method to filter using "loose" comparisons.
I am new to laravel and confused about some query methods.
find($id) is useful and returns a nice array, but sometimes I need to select by other fields rather than id.
The Laravel document said I could use where('field', '=', 'value') and return a bunch of data, which is fine.
What I can't understand is why I need to add ->first() every time, even if I am pretty sure there is only one single row matches the query.
It goes like this:
$query->where(..)->orderBy(..)->limit(..) etc.
// you can chain the methods as you like, and finally you need one of:
->get($columns); // returns Eloquent Collection of Models or array of stdObjects
->first($columns); // returns single row (Eloquent Model or stdClass)
->find($id); // returns single row (Eloquent Model or stdClass)
->find($ids); // returns Eloquent Collection
// those are examples, there are many more like firstOrFail, findMany etc, check the api
$columns is an array of fields to retrieve, default array('*')
$id is a single primary key value
$ids is an array of PKs, this works in find method only for Eloquent Builder
// or aggregate functions:
->count()
->avg()
->aggregate()
// just examples here too
So the method depends on what you want to retrieve (array/collection or single object)
Also the return objects depend on the builder you are using (Eloquent Builder or Query Builder):
User::get(); // Eloquent Colleciton
DB::table('users')->get(); // array of stdObjects
even if I am pretty sure there is only one single row matches the query.
Well Laravel cant read your mind - so you need to tell it what you want to do.
You can do either
User::where('field', '=', 'value')->get()
Which will return all objects that match that search. Sometimes it might be one, but sometimes it might be 2 or 3...
If you are sure there is only one (or you only want the first) you can do
User::where('field', '=', 'value')->first()
get() returns an array of objects (multiple rows)
while
first() returns a single object (a row)
You can of course use get() when you know it will return only one row, but you need to keep that in mind when addressing the result:
using get()
$rez = \DB::table('table')->where('sec_id','=','5')->get();
//will return one row in an array with one item, but will be addressed as:
$myfieldvalue = $rez[0]->fieldname;
using first()
$rez = \DB::table('table')->where('sec_id','=','5')->first();
// will also return one row but without the array, so
$myfieldvalue = $rez->fieldname;
So it depends on how you want to access the result of the query: as an object or as an array, and also depends on what "you know" the query will return.
first() is the equivalent of LIMIT 1 at the end of your SELECT statement. Even if your query would return multiple rows, if you use first() it will only return the first row
I'm confused as to when ->get() in Laravel...
E.G. DB::table('users')->find(1) doesn't need ->get() to retrieve the results, neither does User::find(1)
The laravel docs say "...execute the query using the get or first method..."
I've read the Fluent Query Builder and Eloquent docs but don't understand when the usage of get() is required...
Thanks for the help
Since the find() function will always use the primary key for the table, the need for get() is not necessary. Because you can't narrow your selection down and that's why it will always just try to get that record and return it.
But when you're using the Fluent Query Builder you can nest conditions as such:
$userQuery = DB::table('users');
$userQuery->where('email', '=', 'foo#bar.com');
$userQuery->or_where('email', '=', 'bar#foo.com');
This allows you to add conditions throughout your code until you actually want to fetch them, and then you would call the get() function.
// Done with building the query
$users = $userQuery->get();
For find(n), you retrieve a row based on the primary key which is 'n'.
For first(), you retrieve the first row among all rows that fit the where clauses.
For get(), you retrieve all the rows that fit the where clauses. (Please note that loops are required to access all the rows or you will get some errors).
find returns one row from the database and represent it as a fluent / eloquent object. e.g. SELECT * FROM users WHERE id = 3 is equivalent to DB::table('users')->find(3);
get returns an array of objects. e.g. SELECT * FROM users WHERE created_at > '2014-10-12' is equivalent to DB::table('users')->where('created_at', '>', '2014-10-12')->get() will return an array of objects containing users where the created at field is newer than 4014-10-12.
The get() method will give you all the values from the database that meet your parameters where as first() gets you just the first result. You use find() and findOrFail() when you are searching for a key. This is how I use them:
When I want all data from a table I use the all() method
Model::all();
When I want to find by the primary key:
Model::find(1)->first();
Or
Model::findOrFail(1)->first();
This will work if there is a row with a primary key of one. It should only retrieve one row so I use first() instead of get(). Remember if you deleted the row that used key 1, or don't have data in your table, your find(1) will fail.
When I am looking for specific data as in a where clause:
Model::where('field', '=', 'value')->get();
When I want only the first value of the data in the where clause.
Model::where('field', '=', 'value')->first();
Basically what you need to understand is that get() return a collection(note that one object can be in the collection but it still a collection) why first() returns the first object from the result of the query(that is it returns an object)
#Take_away
Get() return a collection first() return an object
You can use get() method with latest() method to get the latest record that were recently added to your table
For example
$user=Student::latest()->get();
return all the data in descending order