If you have a query where you have one shared ID, e.g. Order ID or Customer ID, but then there are multiple rows for different information about those IDs, you may want to combine that data. You may also think of these as almost like duplicate rows (even if the data isn't a duplicate, you want to merge or filter based on these rows).
In the video below, I have multiple Order IDs, and each has multiple Product items. Some products are custom, others are not customised, which means if I want just the Order IDs with no custom products at all, I need to combine or summarize the rows to filter accurately.
You can easily do this using summarize -> array and then filtering to just get the rows with the correct data. Once you have this query, you can save it and do a right join to your original dataset.
Check out our guide to joins here to get more info!