Question

这是我的原始查询.... 如果您可以看到next_row_date'2013-01-01'的日期，它不是fld_date的最后一条记录，而next_row_date的最后一条记录是'2013-01-15'，则必须为0。

+-----+---+------------+---------------+
| seq | i | fld_Date   | next_row_date |
+-----+---+------------+---------------+
|  41 | 1 | 2012-10-08 | 2012-10-15    |
|  42 | 2 | 2012-10-15 | 2012-10-22    |
|  43 | 3 | 2012-10-22 | 2012-10-29    |
|  44 | 4 | 2012-10-29 | 2012-11-05    |
|  45 | 5 | 2012-11-05 | 2012-11-12    |
|  46 | 6 | 2012-11-12 | 2012-11-19    |
|  47 | 7 | 2012-11-19 | 2013-01-01    |
|  49 | 8 | 2013-01-08 | 2013-01-15    |
+-----+---+------------+---------------+

这是我想要的输出。你可以用这个查询来帮助我吗？

+-----+---+------------+---------------+
| seq | i | fld_Date   | next_row_date |
+-----+---+------------+---------------+
|  41 | 1 | 2012-10-08 | 2012-10-15    |
|  42 | 2 | 2012-10-15 | 2012-10-22    |
|  43 | 3 | 2012-10-22 | 2012-10-29    |
|  44 | 4 | 2012-10-29 | 2012-11-05    |
|  45 | 5 | 2012-11-05 | 2012-11-12    |
|  46 | 6 | 2012-11-12 | 2012-11-19    |
|  47 | 7 | 2012-11-19 | 2013-01-08    |
|  49 | 8 | 2013-01-08 | 0             |
+-----+---+------------+---------------+

SELECT 
        db_lms.a.seq,
        (@i:=@i+1)AS i,
        db_lms.a.fld_Date,
        (db_lms.b.fld_Date)AS next_row_date
 FROM db_lms.lms_savings a, db_lms.lms_savings b, (SELECT @i:=0) ii
WHERE (db_lms.a.seq = db_lms.b.seq-1) ORDER BY db_lms.a.seq ASC;

Answer 1

尝试

SELECT seq, @i := @i + 1 i, fld_Date, next_date
FROM
(
  SELECT seq, @d next_date, @d := fld_Date fld_Date
    FROM lms_savings, (SELECT @d := 0) d
  ORDER BY seq DESC
) q, (SELECT @i := 0) n 
ORDER BY seq

输出：

| SEQ | I |   FLD_DATE |  NEXT_DATE |
-------------------------------------
|  41 | 1 | 2012-10-08 | 2012-10-15 |
|  42 | 2 | 2012-10-15 | 2012-10-22 |
|  43 | 3 | 2012-10-22 | 2012-10-29 |
|  44 | 4 | 2012-10-29 | 2012-11-05 |
|  45 | 5 | 2012-11-05 | 2012-11-12 |
|  46 | 6 | 2012-11-12 | 2012-11-19 |
|  47 | 7 | 2012-11-19 | 2013-01-08 |
|  49 | 8 | 2013-01-08 |          0 |

这是 SQLFiddle 演示。

注意：即使您的样本数据中存在空白，查询仍然有效，例如样本数据47-49

SQL查询如何使用临时字段值获取下一行日期？

1 个答案: