How to Filter Query Results by a Property that is a Reference

Hi, I was wondering how I could filter query results by a property that is a reference? i.e. i have X amount of “downloads” and want to filter them by a given “tag”. “tags” is an array of references.

This could be it:

If you have a document called, for example:

toFilter

that references a set of

tags

that you want to filter by, you could do the following:

This uses the ability of GROQ to chain arbitrarily many

[ ]

( filter-by truth-value of contents ) and

{}

( get these properties from the result-set ), by first getting every document of type

toFilter

(

*[ _type == "toFilter]

), then expanding the references while keeping every field (

{ ..., tags->}

) and then filtering the resulting array of documents by properties on the now expanded tag-field (

[tags.name == $nameOfTagToFilterBy]

).
Note the difference between

*[]

and

[]

here. The

*[]

means “give me EVERY document, and then filter by them by the contents of my

[]

“, while

[]

alone means “for the documents I already have from prior filters, filter them further by these contents”.
Does that help?
🙂

really helpful, thanks