Results of 1 - 10 of about 38 for distinct (0.004 sec.)
- SELECT Clause 14749
- The SELECT clause specifies the list of columns that will be returned by the query. While it appears first in the clause, logically the expressions here are executed only at the end. The SELECT clause can contain arbitrary expressions that
...fix aliases: SELECT res: col1 + col2, root: sqrt(col1) FROM tbl; Select all unique cities from the addresses table: SELECT DISTINCT city FROM addresses; Return the total number of rows in the addresses table: SELECT count(*) FROM addresses; Select all co...Columns can also be selected using regular expressions or lambda functions. See the star expression page for more details. DISTINCT Clause Select all unique cities from the addresses table: SELECT DISTINCT city FROM addresses; The DISTINCT clause can be...d to return only the unique rows in the result – so that any duplicate rows are filtered out. Queries starting with SELECT DISTINCT run deduplication, which is an expensive operation. Therefore, only use DISTINCT if necessary. DISTINCT ON Clause Select o... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/select.html
- Non-Deterministic Behavior 9874
- 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-
...A' AS x UNION SELECT 'B' AS x ); Both results A , B and B , A are correct. Different Results on Different Platforms: array_distinct The array_distinct function may return results in a different order on different platforms : SELECT array_distinct(['A', '...SELECT 'A' AS x UNION SELECT 'B' AS x ) ORDER BY ALL; You can also sort lists using list_sort : sql SELECT list_sort(array_distinct(['A', 'A', 'B', NULL, NULL])) AS i ORDER BY i; It's also possible to introduce a deterministic shuffling .... - https://man.mtool.work/duckdb/2.0/operations_manual/non-deterministic_behavior.h...
- Comparisons 9874
- Comparison Operators The table below shows the standard comparison operators. Whenever either of the input arguments is NULL , the output of the comparison is NULL . Operator Description Example Result < less than 2 < 3 true > greater than
...equal to 4 >= NULL NULL = or == equal NULL = NULL NULL <> or != not equal 2 <> 2 false The table below shows the standard distinction operators. These operators treat NULL values as equal. Operator Description Example Result IS DISTINCT FROM not equal,...including NULL 2 IS DISTINCT FROM NULL true IS NOT DISTINCT FROM equal, including NULL NULL IS NOT DISTINCT FROM NULL true Combination Casting When per... - https://man.mtool.work/duckdb/2.0/sql/expressions/comparison_operators.html
- List Functions 9780
- Function Description list[index] Extracts a single list element using a (1-based) index . list[begin[:end][:step]] Extracts a sublist using slice conventions . Negative values are accepted. list1 && list2 Alias for list_has_any . list1 <->
.... array_concat(list_1, ..., list_n) Alias for list_concat . array_contains(list, element) Alias for list_contains . array_distinct(list) Alias for list_distinct . array_extract(list, index) Extracts the index th (1-based) value from the list . array_fil...t_append(list, element) Appends element to list . list_apply(list, lambda(x)) Alias for list_transform . list_approx_count_distinct(list) Applies aggregate function approx_count_distinct to the list . list_avg(list) Applies aggregate function avg to the...st2) Calculates the Euclidean distance between two points with coordinates given in two inputs lists of equal length. list_distinct(list) Removes all duplicates and NULL values from a list. Does not preserve the original order. list_dot_product(list1, li... - https://man.mtool.work/duckdb/2.0/sql/functions/list.html
- Bitstring Functions 9591
- This section describes functions and operators for examining and manipulating BITSTRING values. Bitstrings must be of equal length when performing the bitwise operands AND, OR and XOR. When bit shifting, the original length of the string is
...operation performed on all bitstrings in a given expression. bitstring_agg(arg) Returns a bitstring with bits set for each distinct position defined in arg . bitstring_agg(arg, min, max) Returns a bitstring with bits set for each distinct position define...| Description | The bitstring_agg function takes any integer type as input and returns a bitstring with bits set for each distinct value. The left-most bit represents the smallest value in the column and the right-most bit the maximum value. If possible...| | Example | bitstring_agg(A) | Tip The combination of bit_count and bitstring_agg can be used as an alternative to count(DISTINCT ...) , with possible performance improvements in cases of low cardinality and dense values. bitstring_agg(arg, min, max) |... - https://man.mtool.work/duckdb/2.0/sql/functions/bitstring.html
- Window Functions 9198
- 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
...urpose window functions, with the minor consequence that the FILTER clause is not available for these but IGNORE NULLS is. DISTINCT Arguments All aggregate window functions support using a DISTINCT clause for the arguments. When the DISTINCT clause is pr...ovided, only distinct values are considered in the computation of the aggregate. This is typically used in combination with the COUNT aggregate...to get the number of distinct elements; but it can be used together with any aggregate function in the system. There are some aggregates that are insens... - https://man.mtool.work/duckdb/2.0/sql/functions/window_functions.html
- Python Client API 8899
- Connection class duckdb. Appender Bases: object append_row ( self , * args ) → None Buffer one row, one value per column, each converted as an executemany parameter would be append_rows ( self , rows : object ) → None Buffer each row of an
...' , window_spec : str = '' , projected_columns : str = '' ) → DuckDBPyRelation Computes a bitstring with bits set for each distinct value in a given expression. Detailed examples can be found at Relational API page . bool_and ( expression : str , groups...= False ) → Any Execute and fetch all rows as a pandas DataFrame. Detailed examples can be found at Relational API page . distinct ( on : object = None ) → DuckDBPyRelation Retrieve distinct rows from this relation object, or the first row of each disti...false. Detailed examples can be found at Relational API page . unique ( unique_aggr : str ) → DuckDBPyRelation Returns the distinct values in a column. Detailed examples can be found at Relational API page . unnest ( * columns : str ) → DuckDBPyRelation... - https://man.mtool.work/duckdb/2.0/clients/python/reference/
- Aggregate Functions 8899
- Examples Produce a single row containing the sum of the amount column: SELECT sum(amount) FROM sales; Produce one row per unique region, containing the sum of amount for each group: SELECT region, sum(amount) FROM sales GROUP BY region; Ret
...FROM sales GROUP BY region HAVING sum(amount) > 100; Return the number of unique values in the region column: SELECT count(DISTINCT region) FROM sales; Return two values, the total sum of amount and the sum of amount minus columns where the region is nor...e cardinality of the result. Aggregate functions can be used in the SELECT , HAVING , and ORDER BY clauses of a SQL query. DISTINCT Clause in Aggregate Functions When the DISTINCT clause is provided, only distinct values are considered in the computation...of the aggregate. This is typically used in combination with the count aggregate to get the number of distinct elements; but it can be used together with any aggregate function in the system. There are some aggregates that are insens... - https://man.mtool.work/duckdb/2.0/sql/functions/aggregates.html
- Relational API 8711
- The Relational API builds a query one step at a time from Python. A relation, a DuckDBPyRelation , is a piece of SQL text: the methods of the Transformation and Functions sections return a new relation whose text extends the one they were c
...a list of columns by the optional groups on the relation. cross Create cross/cartesian product of two relational objects. distinct Retrieve distinct rows from this relation object, or the first row of each distinct value of on . drop Remove columns. exc...─────────┤ │ jacket │ M │ │ jacket │ S │ │ jeans │ M │ │ jeans │ S │ │ t-shirt │ M │ │ t-shirt │ S │ └─────────┴─────────┘ distinct distinct(self, on: object = None) -> DuckDBPyRelation Retrieve distinct rows from this relation object, or the first row o...f each distinct value of on . Parameters on : str, Expression, list, default: None A column name, an Expression or a list of them: keep on... - https://man.mtool.work/duckdb/2.0/clients/python/relational_api.html
- Pivot Internals 8616
- 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
...be created as a result of a PIVOT statement, it must be translated into multiple queries. ENUM types are used to find the distinct values that should become columns. Each ENUM is then injected into one of the PIVOT statement's IN clauses. After the IN c...ities ON year USING sum(population); is initially translated into: CREATE TEMPORARY TYPE __pivot_enum_0_0 AS ENUM ( SELECT DISTINCT year::VARCHAR FROM cities ORDER BY year ); PIVOT cities ON year IN __pivot_enum_0_0 USING sum(population); and finally tra...8 738 US New York City 8015 8175 8772 The rewrite into list-based aggregations shown above is used only when the number of distinct pivot values exceeds the pivot_filter_threshold configuration option (default 20 ). Below that threshold, DuckDB instead u... - https://man.mtool.work/duckdb/2.0/internals/pivot.html
DuckDB 2.0 Documentation / man.mtool.work