Results of 1 - 10 of about 13 for evaluated (0.005 sec.)
- Window Functions 14692
- 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
...using linear interpolation with ORDER BY as the X-axis. first_value(expr[ ORDER BY ordering][ IGNORE NULLS]) Returns expr evaluated at the row that is the first row (with a non-null value of expr if IGNORE NULLS is set) of the window frame. lag(expr[, of...fset[, default]][ ORDER BY ordering][ IGNORE NULLS]) Returns expr evaluated at the row that is offset rows (among rows with a non-null value of expr if IGNORE NULLS is set) before the current row wi...me; if there is no such row, instead return default (which must be of the same type as expr ). Both offset and default are evaluated with respect to the current row. If omitted, offset defaults to 1 and default to NULL . last_value(expr[ ORDER BY ordering... - https://man.mtool.work/duckdb/2.0/sql/functions/window_functions.html
- Constraints 9184
- In SQL, constraints can be specified for tables. Constraints enforce certain properties over data that is inserted into a table. Constraints can be specified along with the schema of the table as part of the CREATE TABLE statement . In cert
...r: NOT NULL constraint failed: students.id Warning Indexes have certain limitations that might result in constraints being evaluated too eagerly, leading to constraint errors such as violates primary key constraint and violates unique constraint . See the...y constraint that is defined in the table. Warning Indexes have certain limitations that might result in constraints being evaluated too eagerly, leading to constraint errors such as violates primary key constraint and violates unique constraint . See the... - https://man.mtool.work/duckdb/2.0/sql/constraints.html
- CREATE MACRO Statement 8956
- The CREATE MACRO statement defines a named, callable SQL expression as a database schema object. Macros may declare parameters, which can be referenced by its expression. Once a macro is created, it may be called by referencing its name and
...by passing values to its parameters; this causes its expression to be evaluated, yielding a value. Depending on the macro type, the value may be scalar, or a TABLE value. The CREATE FUNCTION statement i...operator := , followed by the expression that is to be used as default value. The default value expression is in principle evaluated at definition-time - NOT at run-time. (There are a few exceptions, like CURRENT_SCHEMA . But it's best not to rely on that...matching signature. If an implementation is found, the parameter values are passed and the implementation's expression is evaluated; finally, its resulting value is returned and used in place where the macro was called. This is similar to calling a funct... - https://man.mtool.work/duckdb/2.0/sql/statements/create_macro.html
- Relational API on Pandas 8709
- DuckDB offers a relational API that can be used to chain together query operations. These are lazily evaluated so that DuckDB can optimize their execution. These operators can act on Pandas DataFrames, DuckDB tables or views (which can poin
... - https://man.mtool.work/duckdb/2.0/guides/python/relational_api_pandas.html
- CASE Expression 8481
- The CASE expression performs a switch based on a condition. The basic form is identical to the ternary condition used in many programming languages ( CASE WHEN cond THEN a ELSE b END is equivalent to cond ? a : b ). With a single condition
...expression can be chained, whenever any of the conditions returns true for a single tuple, the corresponding expression is evaluated and returned. CREATE OR REPLACE TABLE integers AS SELECT unnest([1, 2, 3]) AS i; SELECT i, CASE WHEN i = 1 THEN 10 WHEN i... - https://man.mtool.work/duckdb/2.0/sql/expressions/case.html
- Pivot Internals 8357
- PIVOT Pivoting is implemented as a combination of SQL query re-writing and a dedicated PhysicalPivot operator for higher performance. Each PIVOT is implemented as set of aggregations into lists and then the dedicated PhysicalPivot operator
...rating on a list of the column names and a list of the column values. If dynamically unpivoting, the COLUMNS expression is evaluated first to calculate the column list. For example: UNPIVOT monthly_sales ON jan, feb, mar, apr, may, jun INTO NAME month VAL... - https://man.mtool.work/duckdb/2.0/internals/pivot.html
- Partitioned Writes 8252
- Examples Write a table to a Hive partitioned dataset of Parquet files: COPY orders TO 'orders' (FORMAT parquet, PARTITION_BY (year, month)); Write a table to a Hive partitioned dataset of CSV files, allowing overwrites: COPY orders TO 'orde
...PARTITION_PATH CASE WHEN region = 'eu' THEN 'europe' ELSE 'region=' || coalesce(region, 'unknown') END); The expression is evaluated once per partition and its result is cast to VARCHAR . The resulting path must be relative (no leading / ), non-empty, and... - https://man.mtool.work/duckdb/2.0/data/partitioning/partitioned_writes.html
- WITH Clause 8252
- 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.
...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 conditions, DuckDB can inline the CTE into the...query is expensive, materializing it with the MATERIALIZED keyword can improve performance. In this case, complex_query is evaluated only once. WITH t(x) AS MATERIALIZED (⟨complex_query⟩) SELECT * FROM t AS t1, t AS t2, t AS t3; If one wants to disable ma... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/with.html
- Star Expression 8129
- Syntax The * expression can be used in a SELECT statement to select all columns that are projected in the FROM clause. SELECT * FROM tbl; TABLE.* and STRUCT.* The * expression can be prepended by a table name to select only columns from tha
...min_id min_number 1 10 COLUMNS Lambda Function COLUMNS also supports passing in a lambda function . The lambda function is evaluated for all columns present in the FROM clause. Only columns for which the lambda function evaluates to TRUE are retained, and... - https://man.mtool.work/duckdb/2.0/sql/expressions/star.html
- Reference 8005
- This page lists the functions, settings, and log types exposed by the quack extension . For a tour of the protocol, start with the Overview . Function Reference Server Management Function Description quack_serve(⟨listen_uri⟩, ...) Start a s
...sion / global options. Set with SET ⟨name⟩ = ⟨value⟩ or SET GLOBAL . Authentication / Authorization The auth callbacks are evaluated on a fresh server-side connection every time, so the two settings below are global-scoped ( SET GLOBAL ). A plain SET on t... - https://man.mtool.work/duckdb/2.0/quack/reference.html
DuckDB 2.0 Documentation / man.mtool.work