Question

I am struggling, maybe the simplest problem ever. My SQL knowledge pretty much limits me from achieving this. I am trying to build an sql query that should show JobTitle, Note and NoteType. Here is the thing, First job doesn’t have any note but we should see it in the results. System notes never and ever should be displayed. An expected result should look like this

Result:

--------------------------------------------
|ID      |Title      |Note      |NoteType  |
--------------------------------------------
|1       |FirstJob   |NULL      |NULL      |
|2       |SecondJob  |CustomNot1|1         |
|2       |SecondJob  |CustomNot2|1         |
|3       |ThirdJob   |NULL      |NULL      |
--------------------------------------------

.

My query (doesn't work, doesn't display third job)

SELECT J.ID, J.Title, N.Note, N.NoteType
FROM JOB J
LEFT OUTER JOIN NOTE N ON N.JobId = J.ID
WHERE N.NoteType IS NULL OR N.NoteType = 1

My Tables:

My JOB Table
----------------------
|ID      |Title      |
----------------------   
|1       |FirstJob   |
|2       |SecondJob  |
|3       |ThirdJob   |
----------------------


My NOTE Table
--------------------------------------------
|ID      |JobId      |Note      |NoteType  |
--------------------------------------------
|1       |2          |CustomNot1|1         |
|2       |2          |CustomNot2|1         |
|3       |2          |SystemNot1|2         |
|4       |2          |SystemNot3|2         |
|5       |3          |SystemNot1|2         |
--------------------------------------------

Answer 1

This can’t be true together (NoteType can’t be NULL as well as 1 at the same time):

     WHERE N.NoteType IS NULL AND N.NoteType = 1

You may want to use OR instead to check if NoteType is either NULL or 1.

     WHERE N.NoteType IS NULL OR N.NoteType = 1

EDIT: With corrected query, your third job will not be retrieved as JOB_ID is matching but its the row getting filtered out because of the where condition.

Try below as work around to get the third job with null values.

 SELECT J.ID, J.Title, N.Note, N.NoteType
 FROM JOB J
 LEFT OUTER JOIN 
 ( SELECT JOBID NOTE, NOTETYPE FROM NOTE 
   WHERE N.NoteType IS NULL OR N.NoteType = 1) N
 ON N.JobId = J.ID