JSON XPath Column Names

[mrufsvold]

JSON XPath has the form /key1/key2[2]/key3. In this case, key1/key2 points to an array and [2] indicates the 3rd element. It would be nice to have the unpacking maintain the array position so that we could build these types of xpaths.

The problem to achieve this is twofold.

1. The deepest problem is that this will yield a wide table format (a column for each array position. The current implementation only supports tall format (stacking the contents of the array). One possible solution would be to create a index column at the array step, and then, use it to pivot wide at the end.
2. There is no infrastructure for building out the names like this. Right now, the column names are defined at the point that the column definition is created, but we don't know what levels are arrays (much less how long they are) at that point.