I'm trying to join multiple tables together using a `full outer join`, its getting close to the proper result but there are some duplicate rows due to the join clauses. I've got several tables with columns of id, date, value. I'm looking to get a table with one row for each id, date pair that has all the values from each of the tables. 

[Here is a SQLFiddle if you want to play with it.](http://sqlfiddle.com/#!12/7993e/1)

Here's what I've got so far: 

```

SELECT
  COALESCE(T1.ID, T2.ID, T3.ID, t4.id) AS ID,
  COALESCE(T1.event_dt, T2.event_dt, T3.event_dt, t4.event_dt) AS DATE,
  T1.AMT1, T2.AMT2, T3.AMT3, t4.AMT4
FROM T1
FULL OUTER JOIN T2
ON
  T2.id = T1.id
  AND T2.event_dt = T1.event_dt
FULL OUTER JOIN T3
ON
  T3.id = T1.id
  AND T3.event_dt = T1.event_dt
FULL OUTER JOIN T4
ON
  T4.id = T1.id
  AND T4.event_dt = T1.event_dt
ORDER BY ID, DATE

```

This almost works, but I get some duplicate rows when for instance T4 has an ID,event\_dt pair that is not in T1 (as to be expected because thats what I'm joining on). For instance, I'll get something like:

```

1   April, 06 2012 00:00:00+0000    (null)  2   (null)  (null)
1   April, 06 2012 00:00:00+0000    (null)  (null)  (null)  4
1   April, 06 2012 00:00:00+0000    (null)  (null)  3   (null)

```

When I'm looking to get:

```

1   April, 06 2012 00:00:00+0000    (null)   2   3   4

```

Is there a way to flatten/merge those rows together, or is there a better way to go about this altogether?