Head / GroupBy Layer
Select first N rows from each group, similar to pandas groupby().head() or dplyr's group_by() with slice_head().
Example scenarios:
- Latest Products Per Category
| Configuration | Result |
|---|---|
| by=[category] | Group products by category |
| n=3 | Take 3 newest products |
| select=[product_id, launch_date] | Get product details |
- Top Sales Per Region
| Configuration | Result |
|---|---|
| by=[region, quarter] | Group by location and time |
| n=5 | Take 5 highest records |
| select=[sales_id, amount] | Get sales information |
Common applications:
- Most recent events per category
- Top performers by department
- Latest entries per group
- Initial readings per batch
- First responses per survey
Table
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Table
By
[column, ...]Columns to group by. Creates separate groups for selecting first N rows. Examples:
- [customer_id]: First N purchases per customer
- [product_id, store_id]: First N sales per product per store
- [department, year]: First N projects per department yearly
N
u32Number of rows to select from each group (minimum 1). Common values:
- 1: First item only
- 3: Top three entries
- 5: Top five records
- 10: Top ten items
Select
[column, ...]Columns to include in the result. Default ['*'] selects all columns. Examples:
- [timestamp, value]: Time and measurement
- [order_id, amount]: Order details
- [student_id, score]: Student performance