Results of 1 - 10 of about 30 for Constant (0.006 sec.)
- Execution Format 14312
- Vector is the container format used to store in-memory data during execution. DataChunk is a collection of Vectors, used for instance to represent a column list in a PhysicalProjection operator. Data Flow DuckDB uses a vectorized query exec
...this is the standard uncompressed vector format. For flat vectors the logical and physical representations are identical. Constant Vectors Constant vectors are physically stored as a single constant value. Constant vectors are useful when data elements...are repeated – for example, when representing the result of a constant expression in a function call, the constant vector allows us to only store the value once. SELECT lst || 'duckdb' FROM ran...literal is the same for every row. In a flat vector, we would have to duplicate the literal duckdb once for every row. The constant vector allows us to only store the literal once. Constant vectors are also emitted by the storage when decompressing from... - https://man.mtool.work/duckdb/2.0/internals/vector.html
- SQL to/from JSON 12736
- DuckDB provides functions to serialize and deserialize SELECT statements between SQL and JSON, as well as executing JSON serialized statements. Function Type Description json_deserialize_sql(json) Scalar Deserialize one or many json seriali
...ments in the same query context as the pragma, although with the limitation that the serialized JSON must be provided as a constant string, i.e., you cannot do PRAGMA json_execute_serialized_sql(json_serialize_sql(...)) . Note that these functions do not...); {"error":false,"statements":[{"node":{"type":"SELECT_NODE","modifiers":[],"cte_map":{"map":[]},"select_list":[{"class":"CONSTANT","type":"VALUE_CONSTANT","alias":"","query_location":7,"query_location_length":1,"literal":{"kind":"INTEGER","text":"2"}}]...s":{"type":"ORDER_MODIFIER"},"distinct":false,"is_operator":true,"export_state":false,"arguments":[{"expression":{"class":"CONSTANT","type":"VALUE_CONSTANT","query_location":7,"query_location_length":1,"literal":{"kind":"INTEGER","text":"1"}}},{"expressi... - https://man.mtool.work/duckdb/2.0/data/json/sql_to_and_from_json.html
- Syntax Highlighting 10901
- Syntax highlighting in the CLI is available for macOS, Linux and Windows. SQL queries that are written in the shell are automatically highlighted using syntax highlighting. There are several components of a query that are highlighted in dif
...d. Below is a list of query components that can be configured. Type Component Default color Keywords keyword green Numeric constants numeric_constant yellow String constants string_constant yellow Comments comment gray Errors error red Continuation conti...re is an alternative set of syntax highlighting colors: .highlight_colors keyword brightred bold .highlight_colors numeric_constant white .highlight_colors string_constant white .highlight_colors comment cyan .highlight_colors error yellow .highlight_col... - https://man.mtool.work/duckdb/2.0/clients/cli/syntax_highlighting.html
- Utility Functions 8984
- Scalar Utility Functions The functions below are difficult to categorize into specific function types and are broadly useful. Name Description alias(column) Return the name of the column. can_cast_implicitly(source_value, target_value) Whet
...NULL value. Accepts 1 or more parameters. Each expression can be a column, literal value, function result, or many others. constant_or_null(arg1, arg2) If arg2 is NULL , return NULL . Otherwise, return arg1 . count_if(x) Aggregate function; returns the n...eSQL compatibility. query( query_string ) Table function that parses and executes the query defined in query_string . Only constant strings are allowed. Warning: this function allows invoking arbitrary queries, potentially altering the database state. qu...onds. Returns NULL . stats(expression) Returns a VARIANT with statistics about the expression. Expression can be a column, constant, or SQL expression. txid_current() Returns the current transaction's identifier, a UBIGINT value. It will assign a new one... - https://man.mtool.work/duckdb/2.0/sql/functions/utility.html
- Overview of DuckDB Internals 8464
- Tip For a detailed explanation of DuckDB internals, see the Design and Implementation of DuckDB Internals ("DiDi") library entry. On this page is a brief description of the internals of the DuckDB engine. Parser The parser converts a query
...sion represents an expression within a SQL statement. This can be e.g., a reference to a column, an addition operator or a constant value. The type of the ParsedExpression indicates what it represents, e.g., a comparison is represented as a ComparisonExp...te an optimized query plan. The following query optimizers are run: Expression Rewriter : Simplifies expressions, performs constant folding Filter Pushdown : Pushes filters down into the query plan and duplicates filters over equivalency sets. Also prune... - https://man.mtool.work/duckdb/2.0/internals/overview.html
- Expression API 8025
- The Expression class represents an instance of an expression . Why Would I Use the Expression API? Use expressions to build filters and computed columns in Python. They are useful when column names or conditions depend on your code. import
...ame expressions, but new code should use the helpers: Helper Older constructor col(name) ColumnExpression(name) lit(value) ConstantExpression(value) when(condition).then(value) CaseExpression(condition, value) fn(name, *args) FunctionExpression(name, *ar...; the comparisons are == , != , < , <= , > and >= ; & , | and ~ are AND , OR and NOT . A Python value in an operation is a constant. This holds for a string too: col("s") == "x" compares the column s with the text x . Use col("x") to compare with the col...umn x , and lit("x") to make a constant explicit: rel = duckdb.sql("SELECT * FROM (VALUES ('x', 'y'), ('y', 'x')) t(s, x)") print(rel.filter(col("s") == col("x"))... - https://man.mtool.work/duckdb/2.0/clients/python/expression.html
- Delta Extension 8025
- The delta extension adds support for the Delta Lake open-source storage format . It is built using the Delta Kernel . The extension reads Delta tables, local and remote, and writes them: it can create tables and append to them. For implemen
...ties that enable a Delta feature, such as deletion vectors, also upgrade the table's protocol as needed. Values can be any constant expression except NULL . Some properties cannot be set at creation, such as 'delta.enableVariantShredding' . To create a t...kipped based on partition values. PUSHDOWN_FILTERS VARCHAR all Filter pushdown mode for file skipping. One of none , all , constant_only , dynamic_only . ATTACH 's3://⟨my_bucket⟩/⟨path⟩' AS my_table ( TYPE delta, PIN_SNAPSHOT true, PUSHDOWN_FILTERS 'cons... - https://man.mtool.work/duckdb/2.0/core_extensions/delta.html
- Enum Data Type 8025
- 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
...RE current_mood = name; -- Equivalent to `WHERE current_mood::VARCHAR = name` -- No rows returned When comparing against a constant string, DuckDB will perform an optimization and try_cast(⟨constant string⟩, enum_type) so that physically we are doing an... - https://man.mtool.work/duckdb/2.0/sql/data_types/enum.html
- Profiling Queries 8025
- DuckDB supports profiling queries via the EXPLAIN and EXPLAIN ANALYZE statements. EXPLAIN To see the query plan of a query without executing it, run: EXPLAIN ⟨query⟩; The output of EXPLAIN contains the estimated cardinalities for each opera
...e the output is the optimized plan, it can differ substantially from the input query (for example through join reordering, constant folding, or subquery introduction). The generated query preserves the result column names, column order, and logical types... - https://man.mtool.work/duckdb/2.0/sql/statements/profiling.html
- R-Tree Indexes 7765
- 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
...rlaps , ST_Covers , ST_CoveredBy , ST_ContainsProperly . One of the arguments to the spatial predicate function must be a "constant" (i.e., an expression whose result is known at query planning time). This is because the query planner needs to know the b...ial predicate" on the indexed geometry column -- Note how the second argument in this case, the ST_MakeEnvelope call is a "constant" SELECT count(*) FROM t1 WHERE ST_Within(geom, ST_MakeEnvelope(45, 45, 65, 65)); 390 We can check for ourselves that an R-... - https://man.mtool.work/duckdb/2.0/core_extensions/spatial/r-tree_indexes.html
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