Question

我想在processID上加入两个MySQL表格，并将其作为报告进行跟踪。

table 1: LMProcess
------------------------------------
| ProcessID | LMNo | Status | Dept | 
------------------------------------
|1          |1001  |1       |Legal |
|2          |1001  |1       |R&D   |
|3          |1001  |1       |D&R   |
|4          |1001  |1       |L&M   |
|5          |1002  |1       |Legal |
|6          |1002  |1       |R&D   |
|7          |1002  |1       |D&R   |
|8          |1002  |1       |L&M   |
------------------------------------

table 2: Recommendation
-----------------------------------
| ID | ProcessID | Recommendation |
-----------------------------------
|    |1          |Yes             |
|    |2          |No              |
|    |3          |Yes             |
|    |4          |Yes             |
|    |5          |Yes             |
|    |6          |No              |
|    |7          |No              |
|    |8          |Yes             |
-----------------------------------

Report: LM File Recommendations by the Departments
----------------------------------
| LMNo | Legal | R&D | D&R | L&M |
----------------------------------
|1001  |Yes    |No   |Yes  |Yes  |
|1002  |Yes    |No   |No   |Yes  |
----------------------------------

Answer 1

你正在尝试执行一个数据透视操作，这是其他一些RDBMS原生支持的东西，但MySQL不支持（因为开发人员认为它真的属于表示层，而不是数据库）。 p>

但是，您可以按LMNo对结果进行分组，并使用MySQL的GROUP_CONCAT()函数来获得所需的结果：

SELECT   LMNo
       , GROUP_CONCAT(IF(Dept='Legal', Recommendation, NULL)) AS `Legal`
       , GROUP_CONCAT(IF(Dept='R&D'  , Recommendation, NULL)) AS `R&D`
       , GROUP_CONCAT(IF(Dept='D&R'  , Recommendation, NULL)) AS `D&R`
       , GROUP_CONCAT(IF(Dept='L&M'  , Recommendation, NULL)) AS `L&M`
FROM     LMProcess JOIN Recommendation USING (ProcessID)
GROUP BY LMNo

需要帮助使用php mysql生成报告

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