Selects · Laravel

# Selects ## 从数据表中取得所有的数据列 ``` $users = DB::table('users')->get(); foreach ($users as $user) { var_dump($user->name); } ``` ## 从数据表中分块查找数据列 ``` DB::table('users')->chunk(100, function($users) { foreach ($users as $user) { // } }); ``` 通过在闭包中返回 false 来停止处理接下来的数据列： ``` DB::table('users')->chunk(100, function($users) { // return false; }); ``` ## 从数据表中取得单一数据列 ``` $user = DB::table('users')->where('name', 'John')->first(); var_dump($user->name); ``` ## 从数据表中取得单一数据列的单一字段 ``` $name = DB::table('users')->where('name', 'John')->pluck('name'); ``` ## 取得单一字段值的列表 ``` $roles = DB::table('roles')->lists('title'); ``` 这个方法将会返回数据表 role 的 title 字段值的数组。你也可以通过下面的方法，为返回的数组指定自定义键值。 ``` $roles = DB::table('roles')->lists('title', 'name'); ``` ## 指定查询子句 (Select Clause) ``` $users = DB::table('users')->select('name', 'email')->get(); $users = DB::table('users')->distinct()->get(); $users = DB::table('users')->select('name as user_name')->get(); ``` ## 增加查询子句到现有的查询中 ``` $query = DB::table('users')->select('name'); $users = $query->addSelect('age')->get(); ``` ## 使用 where 及运算符 ``` $users = DB::table('users')->where('votes', '>', 100)->get(); ``` ## 「or」语法 ``` $users = DB::table('users') ->where('votes', '>', 100) ->orWhere('name', 'John') ->get(); ``` ## 使用 Where Between ``` $users = DB::table('users') ->whereBetween('votes', [1, 100])->get(); ``` ## 使用 Where Not Between ``` $users = DB::table('users') ->whereNotBetween('votes', [1, 100])->get(); ``` ## 使用 Where In 与数组 ``` $users = DB::table('users') ->whereIn('id', [1, 2, 3])->get(); $users = DB::table('users') ->whereNotIn('id', [1, 2, 3])->get(); ``` ## 使用 Where Null 找有未配置的值的数据 ``` $users = DB::table('users') ->whereNull('updated_at')->get(); ``` ## Dynamic Where Clauses You may even use "dynamic" where statements to fluently build where statements using magic methods: ``` $admin = DB::table('users')->whereId(1)->first(); $john = DB::table('users') ->whereIdAndEmail(2, 'john@doe.com') ->first(); $jane = DB::table('users') ->whereNameOrAge('Jane', 22) ->first(); ``` ## 排序(Order By)、分群(Group By) 及 Having ``` $users = DB::table('users') ->orderBy('name', 'desc') ->groupBy('count') ->having('count', '>', 100) ->get(); ``` ## 偏移(Offset) 及限制(Limit) ``` $users = DB::table('users')->skip(10)->take(5)->get(); ```