# 視圖查詢 視圖查詢可以實現不依賴數據庫視圖的多表查詢，并不需要數據庫支持視圖，是JOIN方法的推薦替代方法，例如： ``` Db::view('User', 'id,name') ->view('Profile', 'truename,phone,email', 'Profile.user_id=User.id') ->view('Score', 'score', 'Score.user_id=Profile.id') ->where('score', '>', 80) ->select(); ``` 生成的SQL語句類似于： ``` SELECT User.id,User.name,Profile.truename,Profile.phone,Profile.email,Score.score FROM think_user User INNER JOIN think_profile Profile ON Profile.user_id=User.id INNER JOIN think_socre Score ON Score.user_id=Profile.id WHERE Score.score > 80 ``` > 注意，視圖查詢無需調用`table`和`join`方法，并且在調用`where`和`order`方法的時候只需要使用字段名而不需要加表名。 默認使用`INNER join`查詢，如果需要更改，可以使用： ``` Db::view('User', 'id,name') ->view('Profile', 'truename,phone,email', 'Profile.user_id=User.id', 'LEFT') ->view('Score', 'score', 'Score.user_id=Profile.id', 'RIGHT') ->where('score', '>', 80) ->select(); ``` 生成的SQL語句類似于： ``` SELECT User.id,User.name,Profile.truename,Profile.phone,Profile.email,Score.score FROM think_user User LEFT JOIN think_profile Profile ON Profile.user_id=User.id RIGHT JOIN think_socre Score ON Score.user_id=Profile.id WHERE Score.score > 80 ``` 可以使用別名： ``` Db::view('User', ['id' => 'uid', 'name' => 'account']) ->view('Profile', 'truename,phone,email', 'Profile.user_id=User.id') ->view('Score', 'score', 'Score.user_id=Profile.id') ->where('score', '>', 80) ->select(); ``` 生成的SQL語句變成： ``` SELECT User.id AS uid,User.name AS account,Profile.truename,Profile.phone,Profile.email,Score.score FROM think_user User INNER JOIN think_profile Profile ON Profile.user_id=User.id INNER JOIN think_socre Score ON Score.user_id=Profile.id WHERE Score.score > 80 ``` 可以使用數組的方式定義表名以及別名，例如： ``` Db::view(['think_user' => 'member'], ['id' => 'uid', 'name' => 'account']) ->view('Profile', 'truename,phone,email', 'Profile.user_id=member.id') ->view('Score', 'score', 'Score.user_id=Profile.id') ->where('score', '>', 80) ->select(); ``` 生成的SQL語句變成： ``` SELECT member.id AS uid,member.name AS account,Profile.truename,Profile.phone,Profile.email,Score.score FROM think_user member INNER JOIN think_profile Profile ON Profile.user_id=member.id INNER JOIN think_socre Score ON Score.user_id=Profile.id WHERE Score.score > 80 ```