mysql-基于空值和空值的排序列表

Question

I have a table of users with basic details id, their names and profile photo (link to photo, actually)

CREATE TABLE IF NOT EXISTS `users` (
  `id` int(11) NOT NULL,
  `userName` varchar(60) NOT NULL,
  `photo` varchar(50) NULL,
  `status` int(11) NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=42 DEFAULT CHARSET=latin1;

INSERT INTO `users` (`id`, `userName`,`photo`, `status`) VALUES
(1, 'John', 'john.png',1),
(2, 'Jane', 'jane.png',1),
(3, 'Ali', '',1),

(6, 'Bruce', 'bruce.png',1),

(7, 'Martha', '',1),
(8, 'Sidney', '',1),
(10, 'Charlie', 'charlie.png',1),

(12, 'Elisa', '',1),
(14, 'Samantha', 'samantha.png',1),
(15, 'Hannah', 'hannah.png',1),

(16, 'Hannah', '',1),
(17, 'Kevin', 'kevin1.png',1),
(18, 'Kevin', 'kevin2.png',1),
(19, 'Ruth', '',1);

Not all users have profile picture. I would like to list these users in alphabetic order and also show users who have profile picture in front.

This is the query that I wrote:

select * from users ORDER BY photo DESC ;

It sorts users based on photo value but they are not being shown in alphabetic order.

Is it possible to list these users such that all users who have photos will appear top on the list with [userName] in alphabetic order?

SQL FIDDLE

Answer 1

将''更改为NULL后...

SELECT * FROM users ORDER BY photo IS NULL,username;

Answer 2

You have empty vlaues here. So you can use this way.

SELECT * FROM users ORDER BY if(photo = '' or photo is null,1,0), userName

But in mysql has a method to order null values with (-).

SELECT * FROM users ORDER BY -photo DESC, userName ASC

Here photo column data order as null values last because of DESC order

OR

SELECT * FROM users ORDER BY
CASE WHEN photo IS NULL THEN 1 ELSE 0 END ASC, userName ASC

Answer 3

If you want 1st people without picture and then other (while sorting these 2 groups alphabetically):

select * from users ORDER BY photo,userName ASC ;

Waiting your feed back if it is not exactly what you want.