MySQL merge table, with zero vaules - mysql

Question

Table A name is source
ID | date | valueS | commonID
1 26.8.14 Svalue01 11
2 21.8.14 Svalue02 11
3 25.8.14 Svalue03 11
Table B name is destination
ID | date | valueD | commonID
1 26.8.14 Dvalue01 11
2 21.8.14 Dvalue03 11
3 24.8.14 Dvalue03 11
So currently im using
SELECT a.*, b.* FROM (SELECT * FROM Source WHERE commonID = '11')a JOIN destination b ON a.commonID = b.commonID
But this dont get me the wished result.
i want something sorted by date, and if there is no record for both on the date, one is zero.
example how it should look
ID | date | valueD | commonID | ID | date | valueS | commonID
1 26.8.14 Dvalue01 11 1 26.8.14 Svalue01 11
3 25.8.14 Svalue03 11
3 24.8.14 Dvalue03 11
2 21.8.14 Dvalue03 11 2 21.8.14 Svalue02 11
Is and how would this be possible?
Additional Info:
-Using Mysql 5.5.37 (MariaDB)
-ID is primary on both
-date fields are "timestamp"
-value fields are INT
-ID fields are INT
-Engine is InnoDB
I hope i provided enough information and tried to make a good explained question
thank you for your help

Answer 1

you want to join on the date as that is the determining column so something like this
SELECT
COALESCE(s.id, "") as s_id,
COALESCE(s.date, "") as s_date,
COALESCE(s.valueS, "") as 'valueS',
COALESCE(s.commonID, "") as s_commonID,
COALESCE(d.id, "") as d_id,
COALESCE(d.date, "") as d_date,
COALESCE(d.valueD, "") as 'valueD',
COALESCE(d.commonID, "") as d_commonID
FROM source s
LEFT JOIN destination d on d.date = s.date
AND d.commonID = s.commonID
WHERE d.commonID = 11
UNION
SELECT
COALESCE(s1.id, "") as s_id,
COALESCE(s1.date, "") as s_date,
COALESCE(s1.valueS, "") as 'valueS',
COALESCE(s1.commonID, "") as s_commonID,
COALESCE(d1.id, "") as d_id,
COALESCE(d1.date, "") as d_date,
COALESCE(d1.valueD, "") as 'valueD',
COALESCE(d1.commonID, "") as d_commonID
FROM source s1
RIGHT JOIN destination d1 on d1.date = s1.date
AND d1.commonID = s1.commonID
WHERE d1.commonID = 11
ORDER BY s_date DESC, d_date DESC
DEMO

Answer 2

You need a Full outer Join
SELECT s.id, s.date, s.valueS, d.valueD, d.commonID FROM source s LEFT JOIN destination d ON (s.id = d.id)
UNION
SELECT s.id, s.date, s.valueS, d.valueD, d.commonID FROM source s RIGHT JOIN destination d ON (s.id = d.id);

Answer 3

I would go with a different solution for this problem. This starts by generating a cross product of all the common ids and dates that you want, and then using left join to bring in the other rows.
You only want one value for commonid, so this is slight overkill for your problem:
select s.*, dest.*
from (select 11 as commonid) c cross join
(select date from source union
select date from destination
) d left outer join
source s
on s.commonid = c.commonid and s.date = d.date left outer join
destination dest
on dest.commonid = c.commonid and dest.date = d.date;
But it is readily extendible. If you wanted two common ids, you could use:
select s.*, dest.*
from (select 11 as commonid union all select 12) c cross join
(select date from source union
select date from destination
) d left outer join
source s
on s.commonid = c.commonid and s.date = d.date left outer join
destination dest
on dest.commonid = c.commonid and dest.date = d.date;