SQL - Combine duas tabelas com valor de data diferente

SELECT a.stock_id,
       a.date,
       a.open,
       a.high,
       a.low,
       a.close,
       a.volume,
       a.p_high,
       a.p_low
FROM (
SELECT t1.stock_id,
       t1.date,
       t2.open,
       t2.high,
       t2.low,
       t2.close,
       t2.volume,
       t1.p_high,
       t1.p_low
FROM table1 t1
LEFT JOIN table2 t2 ON t1.date = t2.date
UNION
SELECT t2.stock_id,
       t2.date,
       t2.open,
       t2.high,
       t2.low,
       t2.close,
       t2.volume,
       t1.p_high,
       t1.p_low
FROM table1 t1
RIGHT JOIN table2 t2 ON t1.date = t2.date ) a
WHERE a.stock_id = 3

| STOCK_ID |                            DATE |   OPEN |   HIGH |    LOW |  CLOSE | VOLUME | P_HIGH |  P_LOW |
-------------------------------------------------------------------------------------------------------------
|        3 | February, 26 2013 00:00:00+0000 | (null) | (null) | (null) | (null) | (null) |    100 |     80 |
|        3 | February, 25 2013 00:00:00+0000 | (null) | (null) | (null) | (null) | (null) |    100 |     80 |
|        3 | February, 24 2013 00:00:00+0000 |     90 |    110 |     70 |     90 |    250 |    100 |     80 |
|        3 | February, 23 2013 00:00:00+0000 |     90 |    110 |     70 |     90 |    250 |    100 |     80 |
|        3 | February, 22 2013 00:00:00+0000 |     90 |    110 |     70 |     90 |    250 | (null) | (null) |
|        3 | February, 21 2013 00:00:00+0000 |     90 |    110 |     70 |     90 |    250 | (null) | (null) |