Results of 1 - 6 of about 6 for dimension (0.003 sec.)
- Schema 11461
- Types It is important to use the correct type for encoding columns (e.g., BIGINT , DATE , DATETIME ). While it is always possible to use string types ( VARCHAR , etc.) to encode more specific values, this is not recommended. Strings use mor
...meric values as strings, especially if you intend to perform e.g., join operations on them. Encoding Repeated Strings as a Dimension Table When a wide string column has only a few distinct values that repeat across many rows, you can replace it with a sma...ll integer key that references a separate dimension table . This is the same idea as a star schema, and it keeps the large fact table narrow, which speeds up grouping and joi...ning. (For a fixed, known set of values, the ENUM type achieves a similar effect automatically.) First, build a dimension table that assigns an integer key to each distinct value. Sorting the values keeps the keys stable and improves compressio... - https://man.mtool.work/duckdb/2.0/guides/performance/schema.html
- Spatial Functions 11168
- Function Index Scalar Functions Function Summary DuckDB_PROJ_Compiled_Version Returns a text description of the PROJ library version that this instance of DuckDB was compiled against. DuckDB_Proj_Version Returns a text description of the PR
...meters, using an ellipsoidal model of the earths surface ST_Difference Returns the "difference" between two geometries ST_Dimension Returns the "topological dimension" of a geometry. ST_Disjoint Returns true if the geometries are disjoint ST_Distance Ret...the collection. If no type parameters is provided, the function will return a multi geometry matching the highest "surface dimension" of the contained geometries. E.g. if the collection contains only Points, a MultiPoint will be returned. But if the colle.... Similarly, if the collection contains Polygons, a MultiPolygon will be returned. Contained geometries of a lower surface dimension will be ignored. If the input geometry contains nested GeometryCollections, their geometries will be extracted recursively... - https://man.mtool.work/duckdb/2.0/core_extensions/spatial/functions.html
- Import from Numpy 9176
- It is possible to query Numpy arrays from DuckDB. There is no need to register the arrays manually – DuckDB can find them in the Python process by name thanks to replacement scans . For example: import duckdb import numpy as np columns = {
...LECT * FROM columns").fetchall()) [(1, 9.0), (2, 8.0), (3, 7.0)] Each array supplies one column. DuckDB also accepts a two-dimensional array, treating each outer array as a column. Transpose an array whose outer dimension represents rows before querying i... - https://man.mtool.work/duckdb/2.0/guides/python/import_numpy.html
- Merge Statement for SCD Type 2 8609
- This is a practical, step-by-step guide to using DuckDB's MERGE statement (introduced in v1.4.0) to perform upserts and build Slowly Changing Dimension Type 2 (SCD Type 2) tables . Type 2 SCDs let you keep full historical versions of record
...re old version RETURNING merge_action Optional: shows what happened to each row (INSERT/UPDATE/DELETE) Build an SCD Type 2 Dimension Table We'll track ducks and preserve history whenever their name, breed, or location changes. DuckDB has a frontend notebo... - https://man.mtool.work/duckdb/2.0/guides/sql_features/merge.html
- GROUP BY Clause 8317
- The GROUP BY clause specifies which grouping columns should be used to perform any aggregations in the SELECT clause. If the GROUP BY clause is specified, the query is always an aggregate query, even if no aggregations are present in the SE
...prevents duplication). See examples below and additional examples in the “Friendlier SQL with DuckDB” blog post . Multiple Dimensions Normally, the GROUP BY clause groups along a single dimension. Using the GROUPING SETS , CUBE or ROLLUP clauses it is pos...sible to group along multiple dimensions. See the GROUPING SETS page for more information. Grouping by UNNEST New Grouping by UNNEST was introduced in DuckDB 2.0.... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/groupby.html
- List Functions 6050
- Function Description list[index] Extracts a single list element using a (1-based) index . list[begin[:end][:step]] Extracts a sublist using slice conventions . Negative values are accepted. list1 && list2 Alias for list_has_any . list1 <->
...5, 3); [2, 5] generate_subscripts(arr, dim) The generate_subscripts(arr, dim) function generates indexes along the dim th dimension of array arr . SELECT generate_subscripts([4, 5, 6], 1) AS i; i 1 2 3 Date Ranges Date ranges are also supported for TIMES... - https://man.mtool.work/duckdb/2.0/sql/functions/list.html
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