Oracle unpivot while adding dates

I have these two tables linked by a simple key, one contains the project name and its start date and the other the planning, which look something like this:

projects
ID      NAME  START_DATE
1       foo   01/01/2017
2       barr  01/02/2017

planning
PRJ    M0    M1    M2
1      70    75    80
2      50    60    70

Could someone help me to join these two tables in order to produce:

PRJ    DATE        PLAN
1      01/01/2017  70
1      01/02/2017  75
1      01/03/2017  80
2      01/02/2017  50
2      01/03/2017  60
2      01/04/2017  70

unpivot seems to be useful here, but I haven't got much practice with it.

thanks

Solution

Consider running an UNPIVOT in a CTE. Then, in main query calculate a row number to which can be used to add days to START_DATE.

Also, consider not storing data in a wide format with M* columns but long format of original value and indicator columns. Otherwise queries like below will be complex.

WITH master AS
  (SELECT *
   FROM planning
   UNPIVOT ("PLAN" FOR M_COLS IN (M0, M1, M2))  -- BUILD OUT LIST IN APP CODE
  )

SELECT m.PRJ, p.START_DATE + m.row_num AS m."DATE", m."PLAN"
FROM projects p
INNER JOIN 
   (SELECT PRJ, "PLAN", ROW_NUMBER() 
                        OVER (PARTITION BY PRJ ORDER BY PRJ) - 1 AS row_num
    FROM master) AS m
ON p.ID = m.PRJ;