camille

$email = DB::table('users')->where('name', 'John')->value('email');

比如users里面查看name重复的数据，用下面的SQL就行

SELECT 
  a.*, 
  b.* 
FROM 
  users AS a, 
  users AS b 
WHERE 
  (
    a.`name` = b.name 
    OR a.name IS NULL 
    AND b.name IS NULL
  ) 
  AND a.ID < b.ID;

删除使用

DELETE a
FROM users as a, users as b
WHERE
          (a.`name`   = b.name OR a.name IS NULL AND b.name IS NULL)
        AND a.ID < b.ID;