查找給出PK和下一個和前一行的位置爲一個結果行中的問題

Question

表（條紋不必要的cols）：

car_id INT(11) PK 
url VARCHAR(100) 
signup TIMESTAMP 

默認列表查詢看起來像：

SELECT car_id, url FROM car ORDER By signup DESC 

現在我需要在列表查詢中查找結果集中汽車的位置。以及上一行和下一行的網址。

我已經嘗試了很多不同的方法，我終於不知道它是否可能。 （在一個查詢中）。

任何幫助查詢或指向正確的方向將非常感激。

編輯：

所期望的結果將是：

pos, nextid, nexturl, previd, prevurl 

Answer 1

嘗試這一個 -

+行位置

SELECT car_id, url, signup, CONCAT(pos1, '/', @p1) position FROM (
    SELECT 
    c.*, 
    @p1:=@p1+1 pos1, 
    @p2:=IF(car_id = 3 AND @p2 IS NULL, @p1, @p2) 
    FROM 
    cars c, 
    (SELECT @p1:=0, @p2:=NULL) t 
    ORDER BY 
    signup 
) t 
WHERE 
    pos1 BETWEEN @p2 - 1 AND @p2 + 1 

---

您寫道： 期望的結果將是：POS機，nextid，nexturl，previd，prevurl

嘗試此查詢：

SELECT 
    @p2 pos, 
    MAX(IF(pos1 > @p2, car_id, NULL)) nextid, 
    MAX(IF(pos1 > @p2, url, NULL)) nexturl, 
    MAX(IF(pos1 < @p2, car_id, NULL)) previd, 
    MAX(IF(pos1 < @p2, url, NULL)) prevurl 
FROM (
    SELECT 
    c.*, 
    @p1:=@p1+1 pos1, 
    @p2:=IF(car_id = 3 AND @p2 IS NULL, @p1, @p2) 
    FROM 
    cars c, 
    (SELECT @p1:=0, @p2:=NULL) t 
    ORDER BY 
    signup 
) t 
WHERE 
    pos1 BETWEEN @p2 - 1 AND @p2 + 1 

Answer 2

(SELECT car_id, url FROM car WHERE car_id = ?) 
UNION 
(SELECT car_id, url FROM car WHERE signup > (SELECT signup FROM car WHERE car_id = ?) ORDER By signup ASC LIMIT 1) 
UNION 
(SELECT car_id, url FROM car WHERE signup < (SELECT signup FROM car WHERE car_id = ?) ORDER By signup DESC LIMIT 1) 

Answer 3

SELECT 
    @previd AS previousid, 
    @prevurl AS previousurl, 
    @previd:=@id AS currentid, 
    @prevurl:=@url AS currenturl, 
    @id:=car_id AS nextid, 
    @url:=url AS nexturl 
FROM 
    (SELECT @previd:=0) AS initprevid, 
    (SELECT @prevurl:='') AS initprevurl, 
    (SELECT @id:=0) AS initid, 
    (SELECT @url:='') AS initurl, 
    car 
WHERE currentid=<whatever> 
ORDER BY 
    car.signup DESC 

您可以過濾掉虛假currentid = 0