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DuckDB converts JSON text columns into typed columns directly in SQL

duckdb.org by The DuckDB team 7 min read Editor score 7/10

DuckDB can infer and adjust a schema from JSON stored in a VARCHAR column, then produce typed columns without exporting the data to a file. This removes an unnecessary round trip from common analytics and ingestion workflows.

What

DuckDB can turn JSON stored in a VARCHAR table column into typed columns directly in SQL, without writing it to a file first.

How

Casting the column to JSON lets json_group_structure merge the structures of its values into one schema, including keys that appear in only some rows.

Why it matters

Direct conversion avoids a file round trip, while schema inference can avoid repeatedly parsing JSON for each extracted field.

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