需要幫助以使用php mysql生成報告

Question

我想在processID上加入兩個MySQL表，並得到以下結果作為報告。

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

您正在嘗試執行數據透視操作，這是其他一些RDBMS本身支持的，但是MySQL不支持（因為開發人員認為它確實屬於表示層而不是數據庫）。

但是，您可以按LMNo將結果LMNo並使用MySQL的GROUP_CONCAT()函數獲得所需的結果：

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