GROQ: Query products through shopifyProduct variants to find references

When working with nested references in a Shopify + Sanity schema, the key is using GROQ's in operator combined with the reference access operator (->) to traverse through multiple levels of references.

Based on your schema structure where:

• product documents have a store object (or similar)
• That object contains a variants array with references to productVariant documents
• Each productVariant has an array field (like attributes) containing references to your custom attribute documents

The solution is to use the in operator to check if a specific value exists anywhere in the dereferenced chain:

*[_type == 'product' && 'your-attribute-id' in store.variants[]->attributes[]->_id]

Or if you're looking for a specific field value within the attribute:

*[_type == 'product' && 'apparel_color' in store.variants[]->attributes[].attribute->key]

How this works:

1. store.variants[]-> dereferences all variant references in the array
2. attributes[] accesses the attributes array in each dereferenced variant
3. .attribute-> (if attributes contain references) or just -> dereferences each attribute reference
4. Finally, access the field you want to match against (like key, _id, etc.)
5. The in operator checks if your target value exists anywhere in the resulting flattened array

GROQ automatically flattens nested arrays when you chain array accessors ([]), which makes this pattern work elegantly for deeply nested references.

You can learn more about the references() function and the reference access operator (->) in the GROQ documentation. While references() is great for direct references, the in operator with dereferencing is more flexible for these nested relationship queries.