Join Distinct or First - sql

Question

I have a table structure for SalesItems, and Sales.
SalesItems is setup something like this
| SaleItemID | SaleID | ProductID | ProductType |
| 1 | 1 | 1 | 1 |
| 2 | 1 | 2 | 2 |
| 3 | 1 | 15 | 1 |
| 4 | 2 | 5 | 2 |
| 5 | 3 | 1 | 1 |
| 6 | 3 | 8 | 5 |
And Sales is setup something like this
| Sale | Cash |
| 1 | 1.00 |
| 2 | 10.00 |
| 3 | 28.50 |
I am trying to export a basic 'Daily History' that uses joins to spit out the information like this.
| Date | StoreID | Type1Sales | Type2Sales | ... | Cash Taken |
| 5/2 | 50 | 50 | 40 | ... | 39.50 |
| 5/3 | 50 | 10 | 32.50 | ... | 48.50 |
The issue I'm having is if I do an inner join From Sales to Sales Items, I'll end up with this.
| SaleItemID | SaleID | ProductID | ProductType | Sale | Cash |
| 1 | 1 | 1 | 1 | 1 | 1.00 |
| 2 | 1 | 2 | 2 | 1 | 1.00 |
| 3 | 1 | 15 | 1 | 1 | 1.00 |
| 4 | 2 | 5 | 2 | 2 | 10.00 |
| 5 | 3 | 1 | 1 | 3 | 28.50 |
| 6 | 3 | 8 | 5 | 3 | 28.50 |
So if I do a SUM(Cash), then I'll end up returning $70.00, instead of the correct $39.50. I'm not the best with joins, so I've been researching outer joins and such, but none of those seem to work as it's still matching up. Is there a way to only match on the FIRST instance, and return NULL for the rest? For example, something like this
| SaleItemID | SaleID | ProductID | ProductType | Sale | Cash |
| 1 | 1 | 1 | 1 | 1 | 1.00 |
| 2 | 1 | 2 | 2 | 1 | NULL |
| 3 | 1 | 15 | 1 | 1 | NULL |
| 4 | 2 | 5 | 2 | 2 | 10.00 |
| 5 | 3 | 1 | 1 | 3 | 28.50 |
| 6 | 3 | 8 | 5 | 3 | NULL |
Or do you have any other suggestions for returning back the correct amount of Cash for each particular day?

Answer 1

Use DISTINCT(SaleID) in your SELECT to return a single row for each Sale ID.