如何从mysql结果中选择第一个和最后一个数据行？

Question

SELECT * from User returns 75 users. Is it possible to select 1st user, and 75th user without doing while($row = mysql_fetch_assoc($result)) ?? and how?

UPDATE

Just to be more clear: I need to have SELECT * as I need the first and 75th user before I do while mysql_fetch_assoc so ASC, DESC, LIMIT answers not required.

Answer 1

SELECT * from User LIMIT 1
UNION
SELECT * from User LIMIT 74,1

---

Edit

@Kay: PHP can't change the internal order of the resultset after it's created.

If the query always returns 75 rows then the only way to access the 1st and the 75th before anything else would be to use mysql_data_seek which moves the internal result pointer:

$result = mysql_query('SELECT * from User');

mysql_data_seek($result, 1);
$row1 = mysql_fetch_assoc($result);

mysql_data_seek($result, 75);
$row75 = mysql_fetch_assoc($result);

Note that if the above is followed by a while , the pointer must be reset to a suitable position.

Answer 2

If you can sort it, you can.

Select * from User order by [something] asc limit 1

and

Select * from User order by [something] desc limit 1

Answer 3

假设您将 'id' 作为主键，并且您需要最后一个（不是第 75 个），您可以尝试以下操作：

SELECT * FROM User WHERE id IN ((SELECT min(id) FROM user b), (SELECT max(id) FROM user c)) 

Answer 4

SELECT 
(SELECT column FROM table WHERE [condition] ORDER BY column LIMIT 1) as 'first',
(SELECT column FROM table WHERE [condition] ORDER BY column DESC LIMIT 1) as 'last'

Answer 5

SELECT  u.*
FROM    Users u
        INNER JOIN (
          SELECT MIN(UserID) AS UserID FROM Users
          UNION ALL SELECT MAX(UserID) FROM Users
        ) um ON um.UserID = u.UserID

Edit

I'm not sure I completely understand what you need but following gets the first and last user followed by everyone else.

SELECT  um.SortOrder, u.*
FROM    Users u
        INNER JOIN (
          SELECT 1 AS SortOrder, MIN(UserID) AS UserID FROM Users
          UNION ALL SELECT 2, MAX(UserID) FROM Users
        ) um ON um.UserID = u.UserID
UNION ALL
SELECT  3 AS SortOrder, u.*
FROM    Users u
        LEFT OUTER JOIN (
          SELECT MIN(UserID) AS UserID FROM Users
          UNION ALL SELECT MAX(UserID) FROM Users
        ) um ON um.UserID = u.UserID
WHERE   um.UserID IS NULL
ORDER BY
        SortOrder

Answer 6

Well, the title of your question is a bit different from the explanation you gave.

I say so cos if you want to select first and last row, it might be different to select 1st and 75th row cos in case the rows increase or reduce, the last might not be the 75th row.

To answer the part of the first and last row, i think you can do this.

select distinct(id) from users where id in ((select max(id) from user), (select min(id) from users));

This query will work well in the hope that users are ordered by id.

But if you are talking about the 1st and 75th row, then i'll settle with @Saul's answer .

Hope this helps.