I want to create this partial index:
db.mycollection.createIndex(
{"firstname": 1, "lastname": 1},
{ partialFilterExpression: { "status": {$exists: false}, "quantity": { $lt: -1 } } } );
but i receive this error:
unsupported expression in partial index: $not\n status exists\n"
How can I do ?
Unfortunately, you don't.
That feature request has been around for quite a while: https://jira.mongodb.org/browse/SERVER-17853
Hopefully they get to it soon, that would be quite useful.
If the status field doesn't have null values, you can use
{ partialFilterExpression: { "status": null, "quantity": { $lt: -1 } } } );