如何从fld_Date的引用字段中获取下一个日期字段？

Question

这是我的问题。

+----+--------+---------+---+------------+------------+
| id | idname | fldname | i | fld_Date   | next_Date  |
+----+--------+---------+---+------------+------------+
|  1 |      1 | Marlon  | 1 | 2013-06-03 | 2013-06-05 |
|  2 |      1 | Marlon  | 2 | 2013-06-05 | 2013-06-07 |
|  3 |      1 | Marlon  | 3 | 2013-06-07 | 2013-06-08 |
|  4 |      1 | Marlon  | 4 | 2013-06-08 | 2013-06-11 |
|  5 |      1 | Marlon  | 5 | 2013-06-11 | 2013-07-01 |
| 19 |      1 | Marlon  | 6 | 2013-07-01 | 2013-07-07 |
| 20 |      1 | Marlon  | 7 | 2013-07-07 | 0          |
|  6 |      2 | Dawn    | 1 | 2013-06-03 | 2013-06-06 |
|  7 |      2 | Dawn    | 2 | 2013-06-06 | 2013-06-08 |
|  8 |      2 | Dawn    | 3 | 2013-06-08 | 2013-06-11 |
|  9 |      2 | Dawn    | 4 | 2013-06-11 | 2013-06-15 |
| 10 |      2 | Dawn    | 5 | 2013-06-15 | 0          |
| 13 |      3 | Jenny   | 1 | 2013-06-14 | 2013-06-15 |
| 11 |      3 | Jenny   | 2 | 2013-06-15 | 2013-06-19 |
| 12 |      3 | Jenny   | 3 | 2013-06-19 | 2013-06-21 |
| 14 |      3 | Jenny   | 4 | 2013-06-21 | 0          |
| 15 |      4 | Rhea    | 1 | 2013-06-21 | 2013-06-22 |
| 16 |      4 | Rhea    | 2 | 2013-06-22 | 2013-06-23 |
| 17 |      4 | Rhea    | 3 | 2013-06-23 | 2013-06-24 |
| 18 |      4 | Rhea    | 4 | 2013-06-24 | 0          |
| 22 |      5 | Chrisha | 1 | 2013-07-07 | 2013-09-07 | <
| 23 |      5 | Chrisha | 2 | 2013-07-08 | 2013-09-07 | <
| 24 |      5 | Chrisha | 3 | 2013-07-11 | 2013-09-07 | <
| 25 |      5 | Chrisha | 4 | 2013-07-16 | 2013-09-07 | <
| 26 |      5 | Chrisha | 5 | 2013-07-17 | 2013-09-07 | <
| 27 |      5 | Chrisha | 6 | 2013-07-22 | 2013-09-07 |
| 21 |      5 | Chrisha | 7 | 2013-09-07 | 0          |
+----+--------+---------+---+------------+------------+

这是我想要的输出...(与上面用<标记的区别)

+----+--------+---------+---+------------+------------+
| id | idname | fldname | i | fld_Date   | next_Date  |
+----+--------+---------+---+------------+------------+
|  1 |      1 | Marlon  | 1 | 2013-06-03 | 2013-06-05 |
|  2 |      1 | Marlon  | 2 | 2013-06-05 | 2013-06-07 |
|  3 |      1 | Marlon  | 3 | 2013-06-07 | 2013-06-08 |
|  4 |      1 | Marlon  | 4 | 2013-06-08 | 2013-06-11 |
|  5 |      1 | Marlon  | 5 | 2013-06-11 | 2013-07-01 |
| 19 |      1 | Marlon  | 6 | 2013-07-01 | 2013-07-07 |
| 20 |      1 | Marlon  | 7 | 2013-07-07 | 0          |
|  6 |      2 | Dawn    | 1 | 2013-06-03 | 2013-06-06 |
|  7 |      2 | Dawn    | 2 | 2013-06-06 | 2013-06-08 |
|  8 |      2 | Dawn    | 3 | 2013-06-08 | 2013-06-11 |
|  9 |      2 | Dawn    | 4 | 2013-06-11 | 2013-06-15 |
| 10 |      2 | Dawn    | 5 | 2013-06-15 | 0          |
| 13 |      3 | Jenny   | 1 | 2013-06-14 | 2013-06-15 |
| 11 |      3 | Jenny   | 2 | 2013-06-15 | 2013-06-19 |
| 12 |      3 | Jenny   | 3 | 2013-06-19 | 2013-06-21 |
| 14 |      3 | Jenny   | 4 | 2013-06-21 | 0          |
| 15 |      4 | Rhea    | 1 | 2013-06-21 | 2013-06-22 |
| 16 |      4 | Rhea    | 2 | 2013-06-22 | 2013-06-23 |
| 17 |      4 | Rhea    | 3 | 2013-06-23 | 2013-06-24 |
| 18 |      4 | Rhea    | 4 | 2013-06-24 | 0          |
| 22 |      5 | Chrisha | 1 | 2013-07-07 | 2013-07-08 | <
| 23 |      5 | Chrisha | 2 | 2013-07-08 | 2013-07-11 | <
| 24 |      5 | Chrisha | 3 | 2013-07-11 | 2013-07-16 | <
| 25 |      5 | Chrisha | 4 | 2013-07-16 | 2013-07-17 | <
| 26 |      5 | Chrisha | 5 | 2013-07-17 | 2013-07-22 | <
| 27 |      5 | Chrisha | 6 | 2013-07-22 | 2013-09-07 |
| 21 |      5 | Chrisha | 7 | 2013-09-07 | 0          |
+----+--------+---------+---+------------+------------+

我的问题是，每次我向fld_Date插入从下一行提前的日期时，next_date行都会受到将提前日期复制到下一行日期的影响……有没有解决这个问题的办法...

以下是我的sql代码，它们正在尝试修复...

SELECT
id,
idname,
fldname,

IF (
@idname = (@idname := idname),
@id :=@id + 1,
@id := 1
) i,
fld_Date,
next_Date
FROM
(
    SELECT
        a.id,
        a.idName,
        a.fldName,
        a.fld_Date,
        IFNULL(b.fld_Date, 0) next_Date
    FROM
        x_table a
    LEFT JOIN x_table b ON a.idname = b.idname
    AND a.fld_Date < b.fld_Date
    GROUP BY
        a.id
) A,
(SELECT @id := 0, @idname := 0) B
 ORDER BY
idName,
a.fld_Date

Answer 1

试试这个：

SELECT id, idname, fldname, IF(@idname=(@idname:=idname), @id:=@id+1, @id:=1) i, fld_Date, next_Date
FROM (SELECT a.id, a.idName, a.fldName, a.fld_Date, IFNULL(b.fld_Date, 0) next_Date
        FROM (SELECT * FROM x_table ORDER BY idName, fld_Date) a 
        LEFT JOIN (SELECT * FROM x_table ORDER BY idName, fld_Date) b ON a.idname = b.idname AND a.fld_Date < b.fld_Date
        GROUP BY a.id ORDER BY idName, fld_Date) A, (SELECT @id:=0, @idname:=0) B