I have a question very similar to this one, but different (aka, I couldn't extend the answer to that one to fit my purposes. Due to the second WHERE condition, specifically).
I have a table which tracks the visit number for customers. There are two types of visits:
| ID | InStoreVisit | InStoreDate | OnlineVisit | OnlineDate |
|----|--------------|-------------|-------------|------------|
| 1 | 1 | 1/1/11 | | |
| 1 | 2 | 1/2/11 | | |
| 1 | | | 1 | 1/3/11 |
| 1 | 3 | 1/4/11 | | |
| 2 | | | 1 | 2/2/12 |
| 2 | 1 | 2/3/12 | | |
| 2 | | | 2 | 2/4/12 |
I need to create a new column which has a sort of 'global visit number' as such:
| ID | InStoreVisit | InStoreDate | OnlineVisit | OnlineDate | GobalVisit |
|----|--------------|-------------|-------------|------------|------------|
| 1 | 1 | 1/1/11 | | | 1 |
| 1 | 2 | 1/2/11 | | | 2 |
| 1 | | | 1 | 1/3/11 | 3 |
| 1 | 3 | 1/4/11 | | | 4 |
| 2 | | | 1 | 2/2/12 | 1 |
| 2 | 1 | 2/3/12 | | | 2 |
| 2 | | | 2 | 2/4/12 | 3 |
I'm getting mixed up on the WHERE condition with which I can do the self-join. Any advice greatly appreciated.
