Results of 1 - 10 of about 14 for materialized (0.001 sec.)
- WITH Clause 14756
- The WITH clause allows you to specify common table expressions (CTEs). Regular (non-recursive) common-table-expressions are essentially views that are limited in scope to a particular query. CTEs can reference each other and can be nested.
...ou can specify column names for CTEs: WITH cte(j) AS (SELECT 42 AS i) FROM cte; CTE Materialization DuckDB handles CTEs as materialized by default, meaning that the CTE is evaluated once and the result is stored in a temporary table. However, under certain c...onditions, DuckDB can inline the CTE into the main query, which means that the CTE is not materialized and its definition is duplicated in each place it is referenced. Inlining is done using the following heuristics: * The CT...E is not referenced more than once. * The CTE does not contain a VOLATILE function. * The CTE is using AS NOT MATERIALIZED and does not use AS MATERIALIZED . * The CTE does not perform a grouped aggregation. Materialization can be explicitly act... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/with.html
- Run Queries 9627
- Overview DuckDB-Wasm provides functions for querying data. Queries are run sequentially: First, create a connection by calling connect . Then, run queries by calling query to materialize the whole result, or send to fetch result chunks lazi
...once and run it repeatedly with different parameter values, binding each value in place of a ? placeholder. Both query() (materialized) and send() (streamed) are available on a prepared statement: // Create a new connection const conn = await db.connect();...re the query const stmt = await conn.prepare(`SELECT v + ? FROM generate_series(0, 10_000) t(v);`); // ... and run it with materialized results await stmt.query(234); // ... or as result chunks for await (const batch of await stmt.send(234)) { // ... } // Cl... - https://man.mtool.work/duckdb/2.0/clients/wasm/query.html
- Samples 8962
- Samples are used to randomly select a subset of a dataset. Examples Select a sample of exactly 5 rows from tbl using reservoir sampling: SELECT * FROM tbl USING SAMPLE 5; Select a sample of approximately 10% of the table using system sampli
...centages. That is because reservoir sampling needs to materialize the entire sample and randomly replace tuples within the materialized sample. The larger the sample size, the higher the performance hit incurred by this process. Reservoir sampling also incur...ce Avoid using reservoir sampling with large sample sizes if possible. Reservoir sampling requires the entire sample to be materialized in memory. bernoulli Bernoulli sampling can only be used when a sampling percentage is specified. It is rather straightfor... - https://man.mtool.work/duckdb/2.0/sql/samples.html
- CREATE VIEW Statement 8822
- The CREATE VIEW statement defines a new view in the catalog. Examples Create a simple view: CREATE VIEW view1 AS SELECT * FROM tbl; Create a view or replace it if a view with that name already exists: CREATE OR REPLACE VIEW view1 AS SELECT
...ql FROM duckdb_views() WHERE view_name = 'view1'; Syntax CREATE VIEW defines a view of a query. The view is not physically materialized. Instead, the query is run every time the view is referenced in a query. CREATE OR REPLACE VIEW is similar, but if a view... - https://man.mtool.work/duckdb/2.0/sql/statements/create_view.html
- Order Preservation 8559
- For many operations, DuckDB preserves the order of rows, similarly to data frame libraries such as Pandas. Example Take the following table for example: CREATE TABLE tbl AS SELECT * FROM (VALUES (1, 'a'), (2, 'b'), (3, 'c')) t(x, y); SELECT
...al row order into an explicit column that can be referenced in the operations that don't preserve row order by default. On materialized tables, the rowid pseudo-column can be used to the same effect. The following operations do not guarantee that the row ord... - https://man.mtool.work/duckdb/2.0/sql/dialect/order_preservation.html
- C++ API 8279
- Installation To use the DuckDB C++ API, download the libduckdb archive for your platform. The latest stable version of the DuckDB C++ API is 2.0.0. Warning DuckDB's C++ API is internal. It is not guaranteed to be stable and can change witho
...mes()[col_idx]; cout << (col_idx + 1 < result->ColumnCount() ? "\t" : "\n"); } // Iterate over every row and column of the materialized result for (idx_t row_idx = 0; row_idx < result->RowCount(); row_idx++) { for (idx_t col_idx = 0; col_idx < result->Column... - https://man.mtool.work/duckdb/2.0/clients/cpp.html
- Julia Client 8279
- The DuckDB Julia package provides a high-performance front-end for DuckDB. Much like SQLite, DuckDB runs in-process within the Julia client, and provides a DBInterface front-end. The package also supports multi-threaded execution. It uses J
...using DuckDB.execute() . Instead they can be run with DuckDB.query() instead of DuckDB.execute() and will always return a materialized result. Scanning DataFrames The DuckDB Julia package also provides support for querying Julia DataFrames. Note that the Da... - https://man.mtool.work/duckdb/2.0/clients/tertiary_clients/julia.html
- DuckDB Wasm Client 8279
- Installation To use the DuckDB Wasm client, visit the duckdb-wasm GitHub repository . The latest stable version of the DuckDB WebAssembly client is 2.0.0. DuckDB-Wasm is a version of DuckDB that has been compiled to WebAssembly , the portab
...cally served files. Import Data — registering files and inserting Apache Arrow, CSV, JSON, and Parquet data. Run Queries — materialized and streaming queries, prepared statements, and exporting results. Load Extensions — how extension loading differs from na... - https://man.mtool.work/duckdb/2.0/clients/wasm/overview.html
- Metrics 8017
- DuckDB provides a set of metrics that can be used to monitor the performance and health of the database. Metrics are named ⟨group⟩.⟨metric⟩ , e.g., query.total_time or operator.timing . The set of collected metrics is controlled with the tr
...optimizer.reorder_filter , optimizer.sampling_pushdown , optimizer.join_filter_pushdown , optimizer.extension , optimizer.materialized_cte , optimizer.aggregate_function_rewriter , optimizer.late_materialization , optimizer.cte_inlining , optimizer.row_grou... - https://man.mtool.work/duckdb/2.0/dev/metrics.html
- Query 7877
- The duckdb_query method allows SQL queries to be run in DuckDB from C. This method takes two parameters, a (null-terminated) SQL query string and a duckdb_result result pointer. The result pointer may be NULL if the application is not inter
...b_result_error_type ( duckdb_result * result ); duckdb_query Executes a SQL query within a connection and stores the full (materialized) result in the out_result pointer. If the query fails to execute, DuckDBError is returned and the error message can be ret... - https://man.mtool.work/duckdb/2.0/clients/c/query.html
DuckDB 2.0 Documentation / man.mtool.work