Results of 1 - 10 of about 28 for Semantics (0.001 sec.)
- Set Operations 16238
- Set operations allow queries to be combined according to set operation semantics . Set operations refer to the UNION [ALL] , INTERSECT [ALL] and EXCEPT [ALL] clauses. The vanilla variants use set semantics, i.e., they eliminate duplicates,
...while the variants with ALL use bag semantics. Traditional set operations unify queries by column position , and require the to-be-combined queries to have the same num...columns of different types where necessary. If this is not possible, the UNION clause throws an error. Vanilla UNION (Set Semantics) The vanilla UNION clause follows set semantics, therefore it performs duplicate elimination, i.e., only unique rows will...be included in the result. SELECT * FROM range(2) t1(x) UNION SELECT * FROM range(3) t2(x); x 2 1 0 UNION ALL (Bag Semantics) UNION ALL returns all rows of both queries following bag semantics, i.e., without duplicate elimination. SELECT * FROM ra... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/setops.html
- Non-Deterministic Behavior 9143
- Several operators in DuckDB exhibit non-deterministic behavior. Most notably, SQL uses set semantics, which allows results to be returned in a different order. DuckDB exploits this to improve performance, particularly when performing multi-
...ed behavior . If you would like to make your queries deterministic, see the “Working Around Non-Determinism” section . Set Semantics One of the most common sources of non-determinism is the set semantics used by SQL. E.g., if you run the following query r... - https://man.mtool.work/duckdb/2.0/operations_manual/non-deterministic_behavior.h...
- Pattern Matching 8947
- There are four separate approaches to pattern matching provided by DuckDB: the traditional SQL LIKE operator , the more recent SIMILAR TO operator (added in SQL:1999), a GLOB operator , and POSIX-style regular expressions . LIKE The LIKE ex
...!~ operators perform POSIX regular expression matching, not SIMILAR TO matching. DuckDB follows the same partial-matching semantics by default, see the PostgreSQL compatibility page . Globbing DuckDB supports file name expansion, also known as globbing,...iles: SELECT * FROM glob('*'); file duckdb.exe test.csv test.json test.parquet test2.csv test2.parquet todos.json Globbing Semantics The ** wildcard matches any number of subdirectories, including none, so **/⟨filename⟩ also returns a file named ⟨filename...r versions, ~ and !~ performed full matching. By default, these operators perform partial matching, following PostgreSQL's semantics. This is controlled by the deprecated regex_match_operator_semantics setting. Setting it to full restores the legacy behav... - https://man.mtool.work/duckdb/2.0/sql/functions/pattern_matching.html
- Writing to Iceberg 8865
- The DuckDB iceberg extension supports writing to Iceberg tables when an Iceberg catalog is attached. Writing to a table read directly from storage with iceberg_scan is not supported: the catalog is required to commit the new table metadata.
...' WHERE id = 1; DELETE FROM iceberg_catalog.sales.events WHERE event_time < TIMESTAMP '2026-01-01'; They use merge-on-read semantics and write positional deletes, see Limitations for UPDATE and DELETE . MERGE INTO The MERGE INTO statement is the recommend...TCHED THEN DELETE to express a delete set in the same statement. As with UPDATE and DELETE , MERGE INTO uses merge-on-read semantics and writes positional deletes to the Iceberg table. ALTER TABLE and Schema Evolution The ALTER TABLE statement is supporte...etion vectors for v3 tables). Copy-on-write functionality is not yet supported. DuckDB-Iceberg only supports merge-on-read semantics . If a table has write.update.mode or write.delete.mode properties set to something other than merge-on-read , the operati... - https://man.mtool.work/duckdb/2.0/core_extensions/iceberg/writing_to_iceberg.htm...
- Versioning of Extensions 8733
- Extension Versioning Most software has some sort of version number. Version numbers serve a few important goals: Tie a binary to a specific state of the source code Allow determining the expected feature set Allow determining the state of t
...3.11.0 probably is stable) Just like DuckDB itself , DuckDB extensions have their own version number. To ensure consistent semantics of these version numbers across the various extensions, DuckDB's Core Extensions use a versioning scheme that prescribes h...0.y.z format. In semantic versioning, versions starting with v0 have a special meaning: they indicate that the more strict semantics of regular ( >v1.0.0 ) versions do not yet apply. It basically means that an extension is working towards becoming a stabl...er in the pre-release format? The extension is compiled from the source code corresponding to the tag. Semantic Versioning semantics apply. See the Semantic Versioning specification for details. The extension follows a release cycle where new features are... - https://man.mtool.work/duckdb/2.0/extensions/versioning_of_extensions.html
- IN Operator 8520
- The IN operator checks containment of the left expression inside the collection on the right hand side (RHS). Supported collections on the RHS are tuples, lists, and maps, as well as subqueries that return a single column. The single-column
...SELECT 'English' IN ('CS', 'Math', NULL); NULL IN [val1, val2, ...] (List) The IN operator works on lists according to the semantics used in Python. Unlike for the IN tuple operator , the presence of NULL values on the right hand side of the expression do...'Math', NULL]; true SELECT 'English' IN ['CS', 'Math', NULL]; false IN Map The IN operator works on maps according to the semantics used in Python, i.e., it checks for the presence of keys (not values): SELECT 'key1' IN MAP {'key1': 50, 'key2': 75}; true... - https://man.mtool.work/duckdb/2.0/sql/expressions/in.html
- Overview 8373
- DuckDB's SQL dialect is based on PostgreSQL. DuckDB tries to closely match PostgreSQL's semantics, however, some use cases require slightly different behavior. For example, interchangeability with data frame libraries necessitates order pre
... - https://man.mtool.work/duckdb/2.0/sql/dialect/overview.html
- ALTER VIEW Statement 8307
- The ALTER VIEW statement changes the schema of an existing view in the catalog. Examples Rename a view: ALTER VIEW view1 RENAME TO view2; ALTER VIEW changes the schema of an existing view. All the changes made by ALTER VIEW fully respect th
...e transactional semantics, i.e., they will not be visible to other transactions until committed, and can be fully reverted through a rollback. Note... - https://man.mtool.work/duckdb/2.0/sql/statements/alter_view.html
- WITH Clause 8160
- 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.
...3 3 Aggregate Payloads in USING KEY By default, each payload column (i.e., each column not listed in USING KEY ) uses last semantics: a new row for an existing key overwrites the previous payload value. You can also specify an aggregate function for a pay...s produced for a key are combined using the aggregate function. Payload columns without an aggregate keep the default last semantics. For example, the following query computes the average of all values produced for key 1 : WITH RECURSIVE tbl(a, b) USING K...FROM tbl WHERE b > 0 ) TABLE tbl; a b 1 2.5 The following query maintains the maximum of b , while c uses the default last semantics: WITH RECURSIVE tbl(a, b, c) USING KEY (a, max(b)) AS ( SELECT 1, 5, 'x' UNION ALL SELECT a, b - 1, 'y' FROM tbl WHERE b >... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/with.html
- Pragmas 7947
- The PRAGMA statement is a SQL extension adopted by DuckDB from SQLite. PRAGMA statements can be issued in a similar manner to regular SQL statements. PRAGMA commands may alter the internal state of the database engine, and can influence the
...formation_schema.tables", "position":"14", "type":"Table", "error_subtype":"MISSING_ENTRY" } IEEE Floating-Point Operation Semantics DuckDB follows IEEE floating-point operation semantics. If you would like to turn this off, run: SET ieee_floating_point_o...and -1.0 / 0.0 ) throws an error. To return NULL instead, also set error_on_division_by_zero = false (see below). New The semantics of integer division by zero changed in DuckDB 2.0. Integer division by zero ( 1 // 0 , 1 % 0 , INTERVAL '1' DAY / 0 ) erro... - https://man.mtool.work/duckdb/2.0/configuration/pragmas.html
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