Question

I want to create a view from the following two tables:

Entry:
entry_id
entry_date
entry_amount
user_id

Forecast:
forecast_id
forecast_date
forecast_amount
user_id

Now I want to have a view which combines each entry with its forecast (same user_id and same date). This is fine, but I have a problem with those rows, which have a forecast and no entry, or vice versa.

I would like to still have all entries with no forecasts as well in the database. They should show up with a null values in the forecast fields. And the same for forecasts without entries.

Answer 1

This (FULL OUTER JOIN) command is not available on MySql you will need to use UNION to achieve this as given below

SELECT E.*, F.*
 FROM Entry E
 LEFT JOIN Forecast F ON E.user_id = F.user_id AND E.entry_date = F.forecast_date
UNION ALL
SELECT E.*, F.*
 FROM Forecast F 
 LEFT JOIN Entry E ON E.user_id = F.user_id AND E.entry_date = F.forecast_date