blockParquet的存储模型主要由行组(RowGroup默认128M)、列块(ColumnChuck)、页(Page)组成。Rowgroup: 将数据水平划分成多个行组columnchunk: 行组中.每个列组成一个列块;每个列块连续存储page: 页,将列块分割成多个页.有数据页,字典页,索引页.footer中最后两个字段为一个以4个字节长度的footer的metadata,以及同...
Information Schema the catalog entriesofthe databas Metadata Functions: duckdb_functions() duckdb_tables() duckdb_types duckdb_views() 配置 either theSETstatementorthe PRAGMA statement. 执行计划: 荷兰-The Kingdomofthe Netherlands-尼德兰 Holland一词将变为 Netherlands 风车、围海大堤以及郁金香 荷兰的国家...
这种集成还使 DuckDB 能够在自己和其他无法直接查询的系统之间起到统一层或 "粘合剂" 的作用,促进了数据处理中的转换步骤。 扩展:DuckDB 具有灵活的扩展机制,这对于直接从 JSON 和 Parquet 或直接从 S3 读取数据特别重要,能够大大提高开发人员的体验。 稳定性和效率:DuckDB 旨在处理超出内存限制(虽然有一些限制)的...
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Add support for parquet key-value metadata by @Maxxen in #9126Default to JSON type if objects have an inconsistent structure by @lnkuiper in #9086Add schema parameter to read_parquet by @lnkuiper in #9123[Python] Add the ability to provide a list of files to read_csv by @Tishj in #...
从文件中选择所有列,然后过滤column_A大于100且column_B中以AAA开头的结果 duckdb -s "SELECT * FROM 'yourfile.parquet' WHERE column_A >= 100 AND column_B LIKE 'AAA%' " 读取CSV格式的文件: duckdb -s "SELECT * FROM read_csv_auto('annnot_metadata.csv')"...
Parquet metadata was added in #1905 (per #1899), but it does not seem to include all parquet file metadata. Here's a python script to generate a parquet file, and then print out its schema metadata: from datetime import datetime from pprint import pprint import pandas as pd import pyarrow...
├── parquet.duckdb_extension ├── sqlsmith.duckdb_extension ├── tpcds.duckdb_extension ├── tpch.duckdb_extension └── visualizer.duckdb_extension 3 directories, 11 files that allows for example: carlo@ScroogeMcDuck duckdb % ./build/release/duckdb -unsigned -cmd "SET extension_directo...
Implement #2534 - add parquet_file_metadata function that supports scanning top-level file metadata by @Mytherin in #9793Correctly clean up database path when an error is thrown in attach by @Mytherin in #9792Fix cotangent(0.0): should also throw OutOfRange by @carlopi in #9799...
SELECT * FROM 'myfile.csv'; SELECT * FROM 'myfile.parquet'; Refer to our Data Import section for more information. SQL Reference The documentation contains a SQL introduction and reference. Development For development, DuckDB requires CMake, Python3 and a C++11 compliant compiler. Run make in...