laravel DB操作

Laravel DB操作

引用天才在战斗的文章（如有意见可删除）

天才在战斗

基本查询

select

检索表中的所有行

$users = DB::table('users')->get();

从表检索单个行(name = lilei)

$user = DB::table('users')->where('name', 'lilei')->first();

检索单个列的行(查询出 name = lilei 的 id)

$name = DB::table('users')->where('name','lilei')->pluck('id');

检索一个列值列表(单独查询这一列)

$roles = DB::table('roles')->lists('title');

该方法将返回一个数组标题即为 title。你也可以指定一个自定义的键列返回的数组

$roles = DB::table('roles')->lists('title', 'name');

指定一个Select子句进行查询

$users = DB::table('users')->select('name', 'email')->get();
$users = DB::table('users')->distinct()->get();
$users = DB::table('users')->select('name as user_name')->get();

Select子句添加到一个现有的查询 $query = DB::table('users')->select('name');

$users = $query->addSelect('age')->get();

where

$users = DB::table('users')->where('votes', '>', 100)->get();

OR

$users = DB::table('users')->where('votes', '>', 100)->orWhere('name', 'John')->get();

Where Between

$users = DB::table('users')->whereBetween('votes', array(1, 100))->get();

Where Not Between

$users = DB::table('users')->whereNotBetween('votes', array(1, 100))->get();

Where In With An Array

$users = DB::table('users')->whereIn('id', array(1, 2, 3))->get();
$users = DB::table('users')->whereNotIn('id', array(1, 2, 3))->get();

Using Where Null To Find Records With Unset Values

$users = DB::table('users')->whereNull('updated_at')->get();

Order By, Group By, And Having

$users = DB::table('users')->orderBy('name', 'desc')->groupBy('count')->having('count', '>', 100)->get();

Offset & Limit

$users = DB::table('users')->skip(10)->take(5)->get();

Joins 连接

查询构建器也可以用来编写连接语句。

Basic Join Statement

DB::table('users')
 ->join('contacts', 'users.id', '=', 'contacts.user_id')
 ->join('orders', 'users.id', '=', 'orders.user_id')
 ->select('users.id', 'contacts.phone', 'orders.price')
 ->get();

左连接语句

DB::table('users')
 ->leftJoin('posts', 'users.id', '=', 'posts.user_id')
 ->get();
DB::table('users')
 ->join('contacts', function($join) {
   $join->on('users.id', '=', 'contacts.user_id')->orOn(...);
 })
 ->get();
DB::table('users')
 ->join('contacts', function($join) {
   $join->on('users.id', '=', 'contacts.user_id')
   ->where('contacts.user_id', '>', 5);
 })
 ->get();

分组

有时候, 您可能需要创建更高级的where子句, 如“存在”或嵌套参数分组。Laravel query builder可以处理这些:

DB::table('users')
 ->where('name', '=', 'John')
 ->orWhere(function($query) {
   $query->where('votes', '>', 100)
   ->where('title', '<>', 'Admin');
 })
 ->get();

上面的查询将产生以下SQL:

select * from users where name = 'John' or (votes > 100 and title <> 'Admin')
 Exists Statements
 DB::table('users')
 ->whereExists(function($query) {
   $query->select(DB::raw(1))
   ->from('orders')
   ->whereRaw('orders.user_id = users.id');
 })
 ->get();

上面的查询将产生以下SQL:

select * from users where name = 'John' or (votes > 100 and title <> 'Admin')
 Exists Statements
 DB::table('users')
 ->whereExists(function($query) {
   $query->select(DB::raw(1))
   ->from('orders')
   ->whereRaw('orders.user_id = users.id');
 })
 ->get();

聚合

查询构建器还提供了各种聚合方法,如统计,马克斯,min,avg和总和。

Using Aggregate Methods

$users = DB::table('users')->count();
$price = DB::table('orders')->max('price');
$price = DB::table('orders')->min('price');
$price = DB::table('orders')->avg('price');
$total = DB::table('users')->sum('votes');

Raw Expressions

有时您可能需要使用一个原始表达式的查询。这些表达式将注入的查询字符串,所以小心不要创建任何SQL注入点!创建一个原始表达式,可以使用DB:rawmethod:

Using A Raw Expression

$users = DB::table('users')
 ->select( DB::raw('count(*) as user_count, status') )
 ->where('status', '<>', 1)
 ->groupBy('status')
 ->get();

递增或递减一个列的值

DB::table('users')->increment('votes');
DB::table('users')->increment('votes', 5);
DB::table('users')->decrement('votes');
DB::table('users')->decrement('votes', 5);

您还可以指定额外的列更新:

DB::table('users')->increment('votes', 1, array('name' => 'lilei'));