PostgreSQL 15: Incorrect Aggregate Results with GROUP BY on JSONB Fields
I'm encountering an issue with PostgreSQL 15 where using `GROUP BY` on a JSONB field is producing unexpected aggregate results. I have a table `orders` with a JSONB column `order_details` that contains various keys, including `product_id` and `quantity`. When I run a query to sum the quantities grouped by `product_id`, the results do not seem to match the expected totals. Here's the query I'm using: ```sql SELECT order_details->>'product_id' AS product_id, SUM((order_details->>'quantity')::int) AS total_quantity FROM orders GROUP BY order_details->>'product_id'; ``` However, some product IDs are showing significantly higher totals than I anticipated. I suspect it might be related to how JSONB fields are being handled in the grouping. To troubleshoot, I tried extracting the values into a temporary table to see if it made a difference: ```sql CREATE TEMP TABLE temp_orders AS SELECT order_details->>'product_id' AS product_id, (order_details->>'quantity')::int AS quantity FROM orders; ``` Then I ran: ```sql SELECT product_id, SUM(quantity) AS total_quantity FROM temp_orders GROUP BY product_id; ``` Even with this method, I am getting inflated totals for some products. The `order_details` JSONB field is structured in a way where each order could potentially have multiple entries for the same `product_id`, but I'm not sure if that’s where the issue lies. The aggregate functions seem to be counting them more than once. I also checked for duplicated entries in the `orders` table and didn’t find any. Could this behavior be a result of how PostgreSQL interprets the JSONB data type in aggregation? Any insights or advice on how to resolve this would be greatly appreciated.