Guided Notes

Nested & Repeated Data (JSON)

Querying nested records and arrays β€” BigQuery STRUCT/ARRAY and JSON in SQL.

Flat vs. nested data

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So far every column held one simple value. Nested data packs several related values into one column β€” a pet's owner column holding the owner's name and age together:

owner = {"name": "Magnus", "age": 9}

The alternative is a separate owners table joined by an ID. Nesting keeps related values together and saves a join; flat tables are simpler to query and update.