Question

I have a problem with a sql-statement.
My DB is MySQL 5.1.

I have 2 tables:

day_table 
date(pk)    note    ...
------- -----   ---
2012-03-29  foo ...
2012-03-30  bar ...
2012-03-31  foobar  ...

other_table
id  fk_date     key     value
--  -------     ---     -----
1   2012-03-29  foo     5
2   2012-03-30  bar     9
3   2012-03-30  foo     4
4   2012-03-31  bar     6
5   2012-03-31  foo     1

So I need a query something like this:

SELECT o.value, d.date FROM other_table o join day_table d on (...) where key = "bar" group by d.date;

And I need a result like this:

result_table
date(pk)    value 
------- -----
2012-03-29  0 (or null) <---- THIS IS IMPORTANT!!!
2012-03-30  9       
2012-03-31  6

I know the problem is the join, but I need to get each date in day_table.

Is this possible with (My)SQL?

Best Regards

Answer 1

use left join instead of inner join:

SELECT o.value, d.date FROM day_table o left join other_table d on o.date=d.date and key = "bar" group by d.date;