Question

我将此表命名为＆＃39;值＆＃39;在MySQL数据库中：

sp_id   W   Value_C Top_C
742     11  11.42   1.15
742     12  114.35  2.44
742     13  27.2    0.42
742     14  55.38   6.2
742     15  23.77   16.7
15      11  10.59   9.15
15      12  12.4    12.3
15      13  157.89  0.72
15      14  51.2    1.5
15      15  11.78   0.51
117     11  27.48   0.92
117     12  21.416  0.76
117     13  75.31   0.39
117     14  2.182   0.79
252     11  15.54   0.25
252     12  10.209  0.32
252     13  14.41   0.44
252     14  68.34   2.16

我希望重新排列数据。我希望得到这个：

sp_id  11       11      12      12      13      13      14      14      15      15
742    11.42    1.15    114.35  2.44    27.2    0.42    55.38   6.2     23.77   6.77
15     10.59    9.15    12.4    12.3    157.89  0.72    51.2    1.5     11.78   0.51
117    27.48    0.92    21.416  0.76    75.31   0.39    2.182   0.79    NULL  NULL
252    15.54    0.25    10.209  0.32    14.41   0.44    68.34   2.16    NULL  NULL

我可以将它们作为列，但我很难将它们作为行。当我使用CASE时，我会在很多地方获得NULL。

我如何使用SELECT查询MySQL此子集？

编辑：更正了标题。

Answer 1

如果W值有限，您可以尝试这样的事情：

SQL Fiddle

MySQL 5.5.32架构设置：

CREATE TABLE ValuesTable
    (`sp_id` int, `W` int, `Value_C` decimal(10,2), `Top_C` decimal(10,2))
;

INSERT INTO ValuesTable
    (`sp_id`, `W`, `Value_C`, `Top_C`)
VALUES
    (742, 11, 11.42, 1.15),
    (742, 12, 114.35, 2.44),
    (742, 13, 27.2, 0.42),
    (742, 14, 55.38, 6.2),
    (742, 15, 23.77, 16.7),
    (15, 11, 10.59, 9.15),
    (15, 12, 12.4, 12.3),
    (15, 13, 157.89, 0.72),
    (15, 14, 51.2, 1.5),
    (15, 15, 11.78, 0.51),
    (117, 11, 27.48, 0.92),
    (117, 12, 21.416, 0.76),
    (117, 13, 75.31, 0.39),
    (117, 14, 2.182, 0.79),
    (252, 11, 15.54, 0.25),
    (252, 12, 10.209, 0.32),
    (252, 13, 14.41, 0.44),
    (252, 14, 68.34, 2.16)
;

查询1 ：

SELECT DISTINCT VT.sp_id, 
       VT11.Value_C as 11v, VT11.Top_C as 11t,
       VT12.Value_C as 12v, VT12.Top_C as 12t,
       VT13.Value_C as 13v, VT13.Top_C as 13t,
       VT14.Value_C as 14v, VT14.Top_C as 14t,
       VT15.Value_C as 15v, VT15.Top_C as 15t
FROM ValuesTable VT
LEFT OUTER JOIN ValuesTable VT11 ON VT.sp_id = VT11.sp_id AND VT11.W = 11
LEFT OUTER JOIN ValuesTable VT12 ON VT.sp_id = VT12.sp_id AND VT12.W = 12
LEFT OUTER JOIN ValuesTable VT13 ON VT.sp_id = VT13.sp_id AND VT13.W = 13
LEFT OUTER JOIN ValuesTable VT14 ON VT.sp_id = VT14.sp_id AND VT14.W = 14
LEFT OUTER JOIN ValuesTable VT15 ON VT.sp_id = VT15.sp_id AND VT15.W = 15

<强> Results ：

| SP_ID |   11V |  11T |    12V |  12T |    13V |  13T |   14V |  14T |    15V |    15T |
|-------|-------|------|--------|------|--------|------|-------|------|--------|--------|
|   742 | 11.42 | 1.15 | 114.35 | 2.44 |   27.2 | 0.42 | 55.38 |  6.2 |  23.77 |   16.7 |
|    15 | 10.59 | 9.15 |   12.4 | 12.3 | 157.89 | 0.72 |  51.2 |  1.5 |  11.78 |   0.51 |
|   117 | 27.48 | 0.92 |  21.42 | 0.76 |  75.31 | 0.39 |  2.18 | 0.79 | (null) | (null) |
|   252 | 15.54 | 0.25 |  10.21 | 0.32 |  14.41 | 0.44 | 68.34 | 2.16 | (null) | (null) |

MySQL SELECT行作为连续列

1 个答案: