How to filter out those with empty JSON field?

[sanggonlee]

My logs have a JSON field, like this:

{
  "foo": 5,
  "bar": {}
}

I'd like to filter out logs that have an empty JSON for the "bar" field, like in the above example.

How do I do that? I tried something like 

where len('bar{}') > 0

but didn't work.

Thank you so much

[yuanliu]

Note bar is not an array, therefore bar{} does not exist.  In that sample data, bar is null.  So, to exclude them,

| where isnotnull(bar)

[richgalloway]

Try this.

| where isnotnull("bar.*")