Results of 1 - 10 of about 66 for want to (0.002 sec.)
want (66), to (437)
- Multiple Connections 18075
- For tests whose purpose is to verify that the transactional management or versioning of data works correctly, it is generally necessary to use multiple connections. For example, if we want to verify that the creation of tables is correctly
...transactional, we might want to start a transaction and create a table in con1 , then fire a query in con2 that checks that the table is not accessible...an use multiple connections in the sqllogictests using connection labels . The connection label can be optionally appended to any statement or query . All queries with the same connection label will be executed in the same connection. A test that w...ould verify the above property would look as follows: statement ok con1 BEGIN TRANSACTION statement ok con1 CREATE TABLE integers (i INTEGER); statement error con2 SELECT * FROM integers;... - https://man.mtool.work/duckdb/2.0/dev/sqllogictest/multiple_connections.html
- SQL Introduction 15451
- This page provides an overview of how to perform simple operations in SQL. This tutorial is only intended to give you an introduction and is in no way a complete tutorial on SQL. This tutorial is adapted from the PostgreSQL tutorial . DuckD
...B's SQL dialect closely follows the conventions of the PostgreSQL dialect. The few exceptions to this are listed on the PostgreSQL compatibility page . In the examples that follow, we assume that you have installed the...DuckDB Command Line Interface (CLI) shell. See the installation page for information on how to install the CLI. Tip If you are looking for a comprehensive to SQL introduction, check the slide decks of the “Tabular Dat...turning identifiers, their original cases are preserved . In the SQL command, we first specify the type of command that we want to perform: CREATE TABLE . After that follows the parameters for the command. First, the table name, weather , is given. T... - https://man.mtool.work/duckdb/2.0/sql/introduction.html
- R-Tree Indexes 15180
- The spatial extension provides support for spatial indexing through the R-tree extension index type. Why Should I Use an R-Tree Index? When working with geospatial datasets, it is very common that you want to filter rows based on their spat
...ial relationship with a specific region of interest. Unfortunately, even though DuckDB's vectorized execution engine is pretty fast, this sort of operation does not scale very well to large datasets as it always requi...res a full table scan to check every row in the table. However, by indexing a table with an R-tree, it is possible to accelerate these types of que...ow the bounding box of the query region before the query itself is executed to use the R-tree index scan. In the future we want to enable R-tree indexes to be used to accelerate additional predicate functions and more complex queries such a spatial j... - https://man.mtool.work/duckdb/2.0/core_extensions/spatial/r-tree_indexes.html
- S3 and AWS Authentication 14036
- This page is the entry point for authenticating to S3 and other AWS services from DuckDB. Authentication is configured using secrets , and the detailed reference material lives on the S3 API Support and AWS Extension pages. The sections bel
...ow explain which method to use and link to the relevant reference. Choosing an Authentication Method There are two S3 secret providers. Use the confi...g provider when you have static credentials, and the credential_chain provider when you want DuckDB to fetch credentials automatically through the AWS SDK. Situation Method Reference You have a static access key and...or Service Accounts (IRSA) credential_chain with the web_identity chain Web Identity (IRSA) You run on an EC2 instance and want to use its instance profile credential_chain with the instance chain credential_chain provider You connect to Amazon RDS o... - https://man.mtool.work/duckdb/2.0/core_extensions/httpfs/authentication.html
- Window Functions 13748
- DuckDB supports window functions , which can use multiple rows to calculate a value for each row. Window functions are blocking operators , i.e., they require their entire input to be buffered, making them one of the most memory-intensive o
...perators in SQL. Window functions are available in SQL since SQL:2003 and are supported by major SQL database systems. Examples G...enerate a row_number column to enumerate rows: SELECT row_number() OVER () FROM sales; Tip If you only need a number for each row in a table, you can use...s are cropped to the edge of the partition. RANGE Framing Returning to the power data, suppose the data is noisy. We might want to compute a 7 day moving average for each plant to smooth out the noise. To do this, we can use this window query: SELECT... - https://man.mtool.work/duckdb/2.0/sql/functions/window_functions.html
- Union Type 13624
- A UNION type (not to be confused with the SQL UNION operator ) is a nested type capable of holding one of multiple “alternative” values, much like the union in C. The main difference is that these UNION types are tagged unions and thus alwa
...ys carry a discriminator “tag” which signals which alternative it is currently holding, even if the inner value itself is null. UNION types are th...us more similar to C++17's std::variant , Rust's Enum or the “sum type” present in most functional languages. UNION types must always have at...r member types in general, since the information in the other members not matching the target type would be “lost”. If you want to coerce a UNION into one of its members, you should use the union_extract function explicitly instead. The only exceptio... - https://man.mtool.work/duckdb/2.0/sql/data_types/union.html
- Result Verification 13457
- The standard way of verifying results of queries is using the query statement, followed by the letter I times the number of columns that are expected in the result. After the query, four dashes ( ---- ) are expected followed by the result v
...query II SELECT 42, 84 UNION ALL SELECT 10, 20; ---- 42 84 10 20 For legacy reasons the letters R and T are also accepted to denote columns. Deprecated DuckDB deprecated the usage of types in the sqllogictest. The DuckDB test runner does not use o...r need them internally – therefore, only I should be used to denote columns. NULL Values and Empty Strings Empty lines have special significance for the SQLLogic test runner: they sig..._plain.parquet' tbl(a) WHERE a = 1 OR a = 2 ---- physical_plan <REGEX>:.*PARQUET_SCAN.*Filters: a=1 OR a=2.* If we instead want the result not to contain a snippet of text, we can use the <!REGEX>: modifier. File As results can grow quite large, and... - https://man.mtool.work/duckdb/2.0/dev/sqllogictest/result_verification.html
- Benchmark Suite 13366
- DuckDB has an extensive benchmark suite. When making changes that have potential performance implications, it is important to run these benchmarks to detect potential performance regressions. Getting Started To build the benchmark suite, ru
...n the following command in the DuckDB repository : BUILD_BENCHMARK=1 BUILD_EXTENSIONS='tpch' make Listing Benchmarks To list all available benchmarks, run: build/release.../benchmark/benchmark_runner --list Running Benchmarks Running a Single Benchmark To run a single benchmark, issue the following command: build/release/benchmark/benchmark_runner benchmark/micro/nulls/no_nul...run section, and the restrictions are the same as for a unit test (e.g., no blank lines, etc.) For the FILL benchmark, we want to find all places where the interpolation fails: run SELECT m, k, fill(v) OVER (PARTITION BY k ORDER BY m) as v FROM data... - https://man.mtool.work/duckdb/2.0/dev/benchmark.html
- Enum Data Type 13153
- Name Description ENUM Dictionary representing all possible string values of a column The enum type represents a dictionary data structure with all possible unique values of a column. For example, a column storing the days of the week can be
...ularly interesting for string columns with low cardinality (i.e., fewer distinct values). This is because the column only stores a numerical reference to the string in the enum dictionary, resulting in immense savings in disk storage and faster que...diamonds', 'clubs'); You can also create an enum using a SELECT statement that returns a single column of VARCHAR s. The set of values from the select statement will be deduplicated automatically, and NULL values will be ignored: CREATE TYPE region...M person WHERE current_mood = 'bogus'; -- Equivalent to `WHERE current_mood::VARCHAR = 'bogus'` -- No rows returned If you want to enforce type-safety, cast to the enum explicitly: SELECT * FROM person WHERE current_mood = 'bogus'::mood; -- Conversio... - https://man.mtool.work/duckdb/2.0/sql/data_types/enum.html
- Storage Versions and Format 13061
- Compatibility Backward Compatibility Backward compatibility refers to the ability of a newer DuckDB version to read storage files created by an older DuckDB version. Version 0.10 is the first release of DuckDB that supports backward compati
...bility in the storage format. DuckDB 0.10 can read and operate on files created by the previous DuckDB version – DuckDB 0.9. For future Duck...DB versions, our goal is to ensure that any DuckDB version released after can read files created by previous versions, starting from this release. We...fort basis. While stability of the storage format is important – there are still many improvements and innovations that we want to make to the storage format in the future. As such, forward compatibility may be (partially) broken on occasion. Warning... - https://man.mtool.work/duckdb/2.0/internals/storage.html
DuckDB 2.0 Documentation / man.mtool.work