Question

I want to join two MySQL tables on processID and get following out put as the report.

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

You’re attempting to perform a pivot operation, which is something that some other RDBMS support natively but MySQL does not (as the developers feel it is something that really belongs in the presentation layer, rather than the database).

However, you can group your results by LMNo and use MySQL’s GROUP_CONCAT() function to achieve the desired results:

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