Laravel Version: 8.0
PHP Version: 7.3.0
Database Driver & Version: MySQL 5.7.34
Describe the Bug
When I use paginate for pagination the data it call the count( * ) query every time even I pass the column name like count(['id']), and the count( * ) query scan all row in the table.
Table name is users and it has 45 column
Route
Route::get("users", "UsersController#index");
Controller
namespace App\Http\Controllers\Api\V1;
class UsersController extends Controller
{
public function index()
{
return User::paginate(10 , ['id']);
}
}
Call users route
Telescope showing me that two queries
Actual result
Expected result
Steps To Solution:
The following image shows that I had done changes as per our functionality, It will take the first column name from the passed in the paginate method array of $columns params and that query does not scan all columns of the users tables.
Final Results:
I have tired to solving this issue any other way or idea then please let me know
Its not recommended to ever touch the vendor files, you can always just override the functionality inside of your model, you can also pass in the columns to override the getCountForPagination() and you can also pass the columns to simplePaginate() that doesn't invoke any counting!
In order to optimize the query to count and paginate, you can do it like this:
//We will call the query on the model
$program = Program::query()->getQuery();
//count the query by specific columns
$thePaginationCount = $program->getCountForPagination(['id']);
//paginate the results using simplePaginate and select the columns we want:
$thePaginatedProgram = $program->simplePaginate(10, ['id', 'name']);
return 'test: '.$thePaginatedProgram;
Will result like this:
select count(`id`) as aggregate from `programs`
select `id`, `name` from `programs` limit 11 offset 0
As you can see it will only load what we specify and its very efficient!
Final Note:
If you just want to paginate without the count, you can always call Model::simplePaginate($amount, [$columns...])
https://laravel.com/docs/9.x/pagination#simple-pagination
This eloquent collection provides this result:
$id = Model::where('s_id', $s_id)->pluck('l_id');
print_r($id)
Illuminate\Support\Collection Object
(
[items:protected] => Array
(
[0] => 31242682774
)
)
How do I return only the "31242682774" value as a string and not a collection?
EDIT ANSWER:
All I had to do is:
$id = Model::where('s_id', $s_id)->pluck('l_id')->first();
Any better options?
If you only need a single value, not multiple values, pluck isn't what you want. There is a method called value on Query Builder that returns a single value:
Model::where('s_id', $s_id)->value('l_id');
Laravel 6.x Docs - Query Builder - Retrieving Results - Retrieving A Single Row / Column From A Table value
It compares to when it the process you wanna do it. On the query execution or after. The most common approach would probably be.
$id = Model::where('s_id', $s_id)->first()->l_id;
This will execute after, meaning the query builder will fetch all columns in the row. In general in Laravel you don't that often work with strings and or other abstractions than your model. Model::where('s_id', $s_id)->first() will return your model and select the l_id property on it.
The approach you chosen is the database way, you only select the l_id and return it as a collection and select the first item from there. This is thou a very performance efficient way of doing it since the database does all the work and is very quick at it.
$id = Model::where('s_id', $s_id)->pluck('l_id')->first();
The reason why it is a collection, it is mainly made for selecting multiple id's, so if you query returned multiple rows multiple ids would be returned. Here you can see an example of pluck in conditional queries, where it is most often used.
$teamIds = Team::where('type', 'admin')->pluck('id');
$adminUsers = User::where('team_id', $teamIds)->get();
Your solution is perfect for what you need, just trying to bring clarity on why and a example of how it is often used.
lets say I have 7 columns in table, and I want to select only two of them, something like this
SELECT `name`,`surname` FROM `table` WHERE `id` = '1';
In laravel eloquent model it may looks like this
Table::where('id', 1)->get();
but I guess this expression will select ALL columns where id equals 1, and I want only two columns(name, surname). how to select only two columns?
You can do it like this:
Table::select('name','surname')->where('id', 1)->get();
Table::where('id', 1)->get(['name','surname']);
You can also use find() like this:
ModelName::find($id, ['name', 'surname']);
The $id variable can be an array in case you need to retrieve multiple instances of the model.
By using all() method we can select particular columns from table like as shown below.
ModelName::all('column1', 'column2', 'column3');
Note: Laravel 5.4
You first need to create a Model, that represent that Table and then use the below Eloquent way to fetch the data of only 2 fields.
Model::where('id', 1)
->pluck('name', 'surname')
->all();
Also Model::all(['id'])->toArray() it will only fetch id as array.
Get value of one column:
Table_Name::find($id)->column_name;
you can use this method with where clause:
Table_Name::where('id',$id)->first()->column_name;
or use this method for bypass PhpStorm "Method where not found in App\Models":
Table_Name::query()->where('id','=',$id)->first()->column_name;
in query builder:
DB::table('table_names')->find($id)->column_name;
with where cluase:
DB::table('table_names')->where('id',$id)->first()->column_name;
or
DB::table('table_names')->where('id',$id)->first('column_name');
last method result is array
You can use get() as well as all()
ModelName::where('a', 1)->get(['column1','column2']);
From laravel 5.3 only using get() method you can get specific columns of your table:
YouModelName::get(['id', 'name']);
Or from laravel 5.4 you can also use all() method for getting the fields of your choice:
YourModelName::all('id', 'name');
with both of above method get() or all() you can also use where() but syntax is different for both:
Model::all()
YourModelName::all('id', 'name')->where('id',1);
Model::get()
YourModelName::where('id',1)->get(['id', 'name']);
To get the result of specific column from table,we have to specify the column name.
Use following code : -
$result = DB::Table('table_name')->select('column1','column2')->where('id',1)->get();
for example -
$result = DB::Table('Student')->select('subject','class')->where('id',1)->get();
use App\Table;
// ...
Table::where('id',1)->get('name','surname');
if no where
Table::all('name','surname');
If you want to get a single value from Database
Model::where('id', 1)->value('name');
Also you can use pluck.
Model::where('id',1)->pluck('column1', 'column2');
You can use Table::select ('name', 'surname')->where ('id', 1)->get ().
Keep in mind that when selecting for only certain fields, you will have to make another query if you end up accessing those other fields later in the request (that may be obvious, just wanted to include that caveat). Including the id field is usually a good idea so laravel knows how to write back any updates you do to the model instance.
You can get it like
`PostModel::where('post_status', 'publish')->get(['title', 'content', 'slug', 'image_url']`)
link
you can also used findOrFail() method here it's good to used
if the exception is not caught, a 404 HTTP response is automatically sent back to the user. It is not necessary to write explicit checks to return 404 responses when using these method not give a 500 error..
ModelName::findOrFail($id, ['firstName', 'lastName']);
While most common approach is to use Model::select,
it can cause rendering out all attributes defined with accessor methods within model classes. So if you define attribute in your model:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class User extends Model
{
/**
* Get the user's first name.
*
* #param string $value
* #return string
*/
public function getFirstNameAttribute($value)
{
return ucfirst($value);
}
}
And then use:
TableName::select('username')->where('id', 1)->get();
It will output collection with both first_name and username, rather than only username.
Better use pluck(), solo or optionally in combination with select - if you want specific columns.
TableName::select('username')->where('id', 1)->pluck('username');
or
TableName::where('id', 1)->pluck('username'); //that would return collection consisting of only username values
Also, optionally, use ->toArray() to convert collection object into array.
If you want to get single row and from the that row single column, one line code to get the value of the specific column is to use find() method alongside specifying of the column that you want to retrieve it.
Here is sample code:
ModelName::find($id_of_the_record, ['column_name'])->toArray()['column_name'];
If you need to get one column calling pluck directly on a model is the most performant way to retrieve a single column from all models in Laravel.
Calling get or all before pluck will read all models into memory before plucking the value.
Users::pluck('email');
->get() much like ->all() (and ->first() etc..) can take the fields you want to bring back as parameters;
->get/all(['column1','column2'])
Would bring back the collection but only with column1 and column2
You can use the below query:
Table('table')->select('name','surname')->where('id',1)->get();
If you wanted to get the value of a single column like 'name', you could also use the following:
Table::where('id', 1)->first(['name'])->name;
For getting multiple columns (returns collection) :
Model::select('name','surname')->where('id', 1)->get();
If you want to get columns as array use the below code:
Model::select('name','surname')->where('id', 1)->get()->toArray();
If you want to get a single column try this:
Model::where('id', 1)->first(['column_name'])->column_name;