当数据存在时，mysql查询返回空集

Question

+----+---------+--------------------+----------+------+---------------------+---------+-------------+------------+----------+
| id | pname   | pmail              | pgender  | page | pdetails            | pnumber | ddepartment | date       | time     |
+----+---------+--------------------+----------+------+---------------------+---------+-------------+------------+----------+
|  1 | karuna  |  karuna@gmail.com  |  female  |   21 |  hfsdh gfhdf  shdh  |    2332 |  Surgeon    | 2018-05-15 | 16:00:00 |
+----+---------+--------------------+----------+------+---------------------+---------+-------------+------------+----------+

这是我的数据库表appointment。

每当我执行前两个查询时，它们都会完美运行

select * from appointment;(execute )

select * from appointment where pname = 'karuna';(execute)

但是当我尝试执行这两个查询时，我得到的结果是空集

select *from appointment where pmail='karuna@gmail.com';(empty set (0.00 sec))

select *from appointment where ddepartment='Surgeon';(empty set (0.00 sec))