php 如何在 Laravel Eloquent 查询（或使用查询生成器）中为表添加别名？
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How to alias a table in Laravel Eloquent queries (or using Query Builder)?
提问by prograhammer
Lets say we are using Laravel's query builder:
假设我们正在使用 Laravel 的查询构建器：
$users = DB::table('really_long_table_name')
->select('really_long_table_name.id')
->get();
I'm looking for an equivalent to this SQL:
我正在寻找与此 SQL 等效的语句：
really_long_table_name AS short_name
This would be especially helpful when I have to type a lot of selects and wheres (or typically I include the alias in the column alias of the select as well, and it get's used in the result array). Without any table aliases there is a lot more typing for me and everything becomes a lot less readable. Can't find the answer in the laravel docs, any ideas?
当我必须输入大量选择和 wheres（或者通常我也将别名包含在选择的列别名中，并在结果数组中使用它）时，这将特别有用。没有任何表别名，我的打字量要多得多，而且一切都变得不那么可读了。在laravel 文档中找不到答案，有什么想法吗？
回答by peterm
Laravel supports aliases on tables and columns with AS. Try
Laravel 支持表和列的别名AS。尝试
$users = DB::table('really_long_table_name AS t')
->select('t.id AS uid')
->get();
Let's see it in action with an awesome tinkertool
让我们用一个很棒的tinker工具来看看它的实际效果
$ php artisan tinker
[1] > Schema::create('really_long_table_name', function($table) {$table->increments('id');});
// NULL
[2] > DB::table('really_long_table_name')->insert(['id' => null]);
// true
[3] > DB::table('really_long_table_name AS t')->select('t.id AS uid')->get();
// array(
// 0 => object(stdClass)(
// 'uid' => '1'
// )
// )
回答by AMIB
To use aliases on eloquent models modify your code like this:
要在 eloquent 模型上使用别名，请像这样修改您的代码：
Item
::from( 'items as items_alias' )
->join( 'attachments as att', DB::raw( 'att.item_id' ), '=', DB::raw( 'items_alias.id' ) )
->select( DB::raw( 'items_alias.*' ) )
->get();
This will automatically add table prefix to table names and returns an instance of Itemsmodel. not a bare query result.
Adding DB::rawprevents laravel from adding table prefixes to aliases.
这将自动为表名添加表前缀并返回Items模型的实例。不是一个简单的查询结果。添加DB::raw可防止 Laravel 向别名添加表前缀。
回答by Koushik Das
Here is how one can do it. I will give an example with joining so that it becomes super clear to someone.
下面是如何做到这一点。我将举一个加入的例子，以便对某人变得非常清楚。
$products = DB::table('products AS pr')
->leftJoin('product_families AS pf', 'pf.id', '=', 'pr.product_family_id')
->select('pr.id as id', 'pf.name as product_family_name', 'pf.id as product_family_id')
->orderBy('pr.id', 'desc')
->get();
Hope this helps.
希望这可以帮助。
回答by muinh
To use in Eloquent. Add on top of your model
在 Eloquent 中使用。添加到您的模型之上
protected $table = 'table_name as alias'
protected $table = 'table_name as alias'
//table_name should be exact as in your database
//table_name 应该与您的数据库中的完全相同
..then use in your query like
..然后在您的查询中使用
ModelName::query()->select(alias.id, alias.name)
ModelName::query()->select(alias.id, alias.name)
回答by Carlos h Gonzalez
You can use less code, writing this:
您可以使用更少的代码，这样写：
$users = DB::table('really_long_table_name')
->get(array('really_long_table_name.field_very_long_name as short_name'));
And of course if you want to select more fields, just write a "," and add more:
当然，如果您想选择更多字段，只需写一个“,”并添加更多：
$users = DB::table('really_long_table_name')
->get(array('really_long_table_name.field_very_long_name as short_name', 'really_long_table_name.another_field as other', 'and_another'));
This is very practical when you use a joins complex query
这在您使用连接复杂查询时非常实用
回答by Ahmed Gamal
Same as AMIB answer, for soft delete error "Unknown column 'table_alias.deleted_at'",
just add ->withTrashed()then handle it yourself like ->whereRaw('items_alias.deleted_at IS NULL')
与AMIB答案相同，对于软删除错误“未知列'table_alias.deleted_at'”，只需添加->withTrashed()然后自己处理->whereRaw('items_alias.deleted_at IS NULL')
