Repeat all rows in left table for each unique ID in other table - sql

Question

I have a team of people who are scored on up to three metrics; sales, leads and Hours.
I have a table (tblScores) in MS Access which holds these scores but only if there is any. (e.g if someone had no sales there would be no entry for them for sales)
| USERID | Metric | Score |
----------------------------------
| 20511 | Sales | 12 |
| 20511 | Leads | 9 |
| 20511 | Hours | 8 |
| 20694 | Sales | 10 |
| 20694 | Hours | 7.5 |
I am trying to create an SQL query that will output three records (each possible metric) for each User in the above table including null values where they don't have an entry for that metric. e.g
| USERID | Metric | Score |
----------------------------------
| 20511 | Sales | 12 |
| 20511 | Leads | 9 |
| 20511 | Hours | 8 |
| 20694 | Sales | 10 |
| 20694 | Leads | Null |
| 20694 | Hours | 7.5 |
I have set up another table (tblMetrics) with just these 3 metrics
| Metric |
---------------
| Sales |
| Leads |
| Hours |
and tried to do a left join on the metric table against the score table
SELECT tblMetrics.*, TblScores.UserID, TblScores.Score
FROM tblMetrics LEFT JOIN TblScores ON tblMetrics.Metric = TblScores.Metric;
but it is still not giving the desired output. Does anyone know if this possible?

Answer 1

You need to do a CROSS JOIN first to generate all combinations, then do the LEFT JOIN to find which one are missing and assign NULL
I check access syntaxis and the CROSS JOIN should be write like this
SELECT DISTINCT M.Metric, S.USERID
FROM tblMetric M, tblScore S
And the Left Join should be
SELECT userMetrc.*, S.Score
FROM ( SELECT DISTINCT M.Metric, S.USERID
FROM tblMetric M, tblScore S
) userMetric
LEFT JOIN tblScore S
ON ( userMetric.USERID = S.USERID
AND userMetric.Metric = S.Metric )