问题
I have a couchdb view set up using an array key value, in the format:
[articleId, -timestamp]
I want to query for all entries with the same article id. All timestamps are acceptable.
Right now I am using a query like this:
?startkey=["A697CA3027682D5JSSC",-9999999999999]&endkey=["A697CA3027682D5JSSC",0]
but I would like something a bit simpler.
Is there an easy way to completely wildcard the second key element? What would be the simplest syntax for this?
回答1:
First, as a comment pointed out, there is indeed a special value {} that is ordered after any value, so your query becomes:
startkey=["target ID"]&endkey=["target ID",{}]
This is as equivalent to a wildcard match.
As a side note, there is no need to reverse the ordering in the map function by emitting a negative timestamp, you can reverse the order as an option to the view invocation (your start and end key will be swapped).
startkey=["target ID",{}]&endkey=["target ID"]&descending=true
来源：https://stackoverflow.com/questions/11623154/couchdb-querying-array-key-value-for-first-key-element-only