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,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
~~~