Currently my query looks like so:

```
SELECT start_date, from_id, to_id, from_amount, to_amount
FROM sample_table
WHERE from_id = '123'
OR to_id = '123';

```

However, what I'm really aiming for is one `amount` column in my results which shows `from_amount` WHERE `from_id = 123` and `to_amount` WHERE `to_id = 123`.

So instead of:

```
start_date / from_id / to_id / from_amount / to_amount
2016-01-01 /  '123'  / '456' /     100     /    20
2016-01-07 /  '789'  / '123' /      50     /    75

```

I'd like to return:

```
start_date / amount
2016-01-01 /  100
2016-01-07 /  75

```

I'm assuming I need to use some sort of nested WHERE, but not sure how to set it up.