FirebirdSQL
ANSI SQL2003 Window Functions [CORE1688]
Submitted by: @pmakowski
Jira_subtask_outward CORE2090 Jira_subtask_outward CORE2133 Replaces CORE2689 Jira_subtask_outward CORE2823 Jira_subtask_outward CORE2830 Jira_subtask_outward CORE2869 Jira_subtask_outward CORE3616 Jira_subtask_outward CORE3617 Jira_subtask_outward CORE3618 Jira_subtask_outward CORE3619 Jira_subtask_outward CORE3620 Jira_subtask_outward CORE3621 Jira_subtask_outward CORE3647 Jira_subtask_outward CORE5338 Jira_subtask_outward CORE5346
Votes: 16
After CTE, it would be nice to have ANSI SQL Window Functions
SQL2003 allows for a window_clause in aggregate function calls, the addition of which makes those functions into window functions. SQL2003 specifies the following syntax for window functions:
FUNCTION_NAME(expr) OVER {window_name|(window_specification)} window_specification ::= [window_name][partitioning][ordering][framing] partitioning ::= PARTITION BY value [, value...] [COLLATE collation_name] ordering ::= ORDER [SIBLINGS] BY rule [, rule...] rule ::= {value|position|alias} [ASC|DESC] [NULLS {FIRST|LAST}] framing ::= {ROWS|RANGE} {start|between} [exclusion] start ::= {UNBOUNDED PRECEDING|unsigned-integer PRECEDING|CURRENT ROW} between ::= BETWEEN bound AND bound bound ::= {start|UNBOUNDED FOLLOWING|unsigned-integer FOLLOWING} exclusion ::= {EXCLUDE CURRENT ROW|EXCLUDE GROUP |EXCLUDE TIES|EXCLUDE NO OTHERS}
List of Window Functions CUME_DIST( ) OVER {window_name|(window_specification)} : Calculates the cumulative distribution, or relative rank, of the current row to other rows in the same partition
DENSE_RANK( ) OVER {window_name|(window_specification)} : Assigns a rank to each row in a partition, which should be ordered in some manner. The rank for a given row is computed by counting the number of rows preceding the row in question, and then adding 1 to the result. Rows with duplicate ORDER BY values will rank the same. Unlike the case with RANK( ), gaps in rank numbers will not result from two rows sharing the same rank.
RANK( ) OVER {window_name|(window_specification)} : Assigns a rank to each row in a partition, which should be ordered in some manner. The rank for a given row is computed by counting the number of rows preceding the row in question, and then adding 1 to the result. Rows with duplicate ORDER BY values will rank the same, and will lead to subsequent gaps in rank numbers.
PERCENT_RANK( ) OVER ({window_name|(window_specification)} : Computes the relative rank of a row by dividing that row's rank less 1 by the number of rows in the partition, also less 1
ROW_NUMBER( ) OVER ({window_name|(window_specification)} : Assigns a unique number to each row in a partition.
Modified by: @pcisar
Workflow: jira [ 13816 ] => Firebird [ 14123 ]
Modified by: @asfernandes
assignee: Adriano dos Santos Fernandes [ asfernandes ]
Commented by: Volker Rehn (vr2_s18)
Adriano has asked what to implement first since Philippe's list is fairly big. Please see this link on how it is done in Postgres
http://umitanuki.net/pgsql/wfv03/design.html
and this one for a good introduction and summary on this complex topic
this ticket deserves a higher priority. Even if only partially implemented those features would significantly enhance the toolkit of OLAP users of Firebird.
Commented by: @pmakowski
In my opinion, the priority is to set Window functions (RANK(), ROW_NUMBER())
Commented by: @asfernandes
My intention is to implement early a way for current GROUP BY functions work with OVER ([PARTITION BY ...]) clause. Later, some internal refactoring would be desired to make easy creation of new functions.
Functions as RANK and ROW_NUMBER also requires ORDER BY clause, so they probably will not be the first ones.
Commented by: Volker Rehn (vr2_s18)
the current window function postgres link is
http://umitanuki.net/pgsql/wfv05/design.html
Commented by: @asfernandes
I'm resolving this because there is no immediate plan to implement more subtasks.
Modified by: @asfernandes
status: Open [ 1 ] => Resolved [ 5 ]
resolution: Fixed [ 1 ]
Fix Version: 3.0 Alpha 1 [ 10331 ]
Commented by: @pmakowski
Adriano, did you implemented :
percent_rank() relative rank of the current row: (rank - 1) / (total rows - 1)
cume_dist() relative rank of the current row: (number of rows preceding or peer with current row) / (total rows)
ntile(num_buckets integer) integer ranging from 1 to the argument value, dividing the partition as equally as possible
lag(value any [, offset integer [, default any ]]) returns value evaluated at the row that is offset rows before the current row within the partition; if there is no such row, instead return default. Both offset and default are evaluated with respect to the current row. If omitted, offset defaults to 1 and default to null
lead(value any [, offset integer [, default any ]]) returns value evaluated at the row that is offset rows after the current row within the partition; if there is no such row, instead return default. Both offset and default are evaluated with respect to the current row. If omitted, offset defaults to 1 and default to null
first_value(value any) return value evaluated at the row that is the first row of the window frame
last_value(value any) returns value evaluated at the row that is the last row of the window frame
nth_value(value any, nth integer) returns value evaluated at the row that is the nth row of the window frame (counting from 1); null if no such row
for ref : http://www.postgresql.org/docs/9.1/static/functions-window.html#FUNCTIONS-WINDOW-TABLE
Commented by: @asfernandes
Philippe, of these only LAG and LEAD are already implemented.
Commented by: @pmakowski
ok so I reopen this one and please add sub tasks for percent_rank() cume_dist() ntile(num_buckets integer) first_value(value any) last_value(value any) nth_value(value any, nth integer)
Modified by: @pmakowski
status: Resolved [ 5 ] => Reopened [ 4 ]
resolution: Fixed [ 1 ] =>
Modified by: Sean Leyne (seanleyne)
description: After CTE, it would be nice to have ANSI SQL Window Functions
SQL2003 allows for a window_clause in aggregate function calls, the addition of which makes those functions into window functions. SQL2003 specifies the following syntax for window functions:
FUNCTION_NAME(expr) OVER {window_name|(window_specification)} window_specification ::= [window_name][partitioning][ordering][framing] partitioning ::= PARTITION BY value [, value...] [COLLATE collation_name] ordering ::= ORDER [SIBLINGS] BY rule [, rule...] rule ::= {value|position|alias} [ASC|DESC] [NULLS {FIRST|LAST}] framing ::= {ROWS|RANGE} {start|between} [exclusion] start ::= {UNBOUNDED PRECEDING|unsigned-integer PRECEDING|CURRENT ROW} between ::= BETWEEN bound AND bound bound ::= {start|UNBOUNDED FOLLOWING|unsigned-integer FOLLOWING} exclusion ::= {EXCLUDE CURRENT ROW|EXCLUDE GROUP |EXCLUDE TIES|EXCLUDE NO OTHERS}
List of Window Functions CUME_DIST( ) OVER {window_name|(window_specification)} : Calculates the cumulative distribution, or relative rank, of the current row to other rows in the same partition DENSE_RANK( ) OVER {window_name|(window_specification)} : Assigns a rank to each row in a partition, which should be ordered in some manner. The rank for a given row is computed by counting the number of rows preceding the row in question, and then adding 1 to the result. Rows with duplicate ORDER BY values will rank the same. Unlike the case with RANK( ), gaps in rank numbers will not result from two rows sharing the same rank. RANK( ) OVER {window_name|(window_specification)} : Assigns a rank to each row in a partition, which should be ordered in some manner. The rank for a given row is computed by counting the number of rows preceding the row in question, and then adding 1 to the result. Rows with duplicate ORDER BY values will rank the same, and will lead to subsequent gaps in rank numbers. PERCENT_RANK( ) OVER ({window_name|(window_specification)} : Computes the relative rank of a row by dividing that row's rank less 1 by the number of rows in the partition, also less 1 ROW_NUMBER( ) OVER ({window_name|(window_specification)} : Assigns a unique number to each row in a partition.
=>
After CTE, it would be nice to have ANSI SQL Window Functions
SQL2003 allows for a window_clause in aggregate function calls, the addition of which makes those functions into window functions. SQL2003 specifies the following syntax for window functions:
FUNCTION_NAME(expr) OVER {window_name|(window_specification)} window_specification ::= [window_name][partitioning][ordering][framing] partitioning ::= PARTITION BY value [, value...] [COLLATE collation_name] ordering ::= ORDER [SIBLINGS] BY rule [, rule...] rule ::= {value|position|alias} [ASC|DESC] [NULLS {FIRST|LAST}] framing ::= {ROWS|RANGE} {start|between} [exclusion] start ::= {UNBOUNDED PRECEDING|unsigned-integer PRECEDING|CURRENT ROW} between ::= BETWEEN bound AND bound bound ::= {start|UNBOUNDED FOLLOWING|unsigned-integer FOLLOWING} exclusion ::= {EXCLUDE CURRENT ROW|EXCLUDE GROUP |EXCLUDE TIES|EXCLUDE NO OTHERS}
List of Window Functions CUME_DIST( ) OVER {window_name|(window_specification)} : Calculates the cumulative distribution, or relative rank, of the current row to other rows in the same partition
DENSE_RANK( ) OVER {window_name|(window_specification)} : Assigns a rank to each row in a partition, which should be ordered in some manner. The rank for a given row is computed by counting the number of rows preceding the row in question, and then adding 1 to the result. Rows with duplicate ORDER BY values will rank the same. Unlike the case with RANK( ), gaps in rank numbers will not result from two rows sharing the same rank.
RANK( ) OVER {window_name|(window_specification)} : Assigns a rank to each row in a partition, which should be ordered in some manner. The rank for a given row is computed by counting the number of rows preceding the row in question, and then adding 1 to the result. Rows with duplicate ORDER BY values will rank the same, and will lead to subsequent gaps in rank numbers.
PERCENT_RANK( ) OVER ({window_name|(window_specification)} : Computes the relative rank of a row by dividing that row's rank less 1 by the number of rows in the partition, also less 1
ROW_NUMBER( ) OVER ({window_name|(window_specification)} : Assigns a unique number to each row in a partition.
Commented by: @pmakowski
seems that : framing ::= {ROWS|RANGE} {start|between} [exclusion] start ::= {UNBOUNDED PRECEDING|unsigned-integer PRECEDING|CURRENT ROW} between ::= BETWEEN bound AND bound bound ::= {start|UNBOUNDED FOLLOWING|unsigned-integer FOLLOWING} exclusion ::= {EXCLUDE CURRENT ROW|EXCLUDE GROUP |EXCLUDE TIES|EXCLUDE NO OTHERS}
are not implemeted ?
Commented by: @dyemanov
Philippe, there was no indication that the whole specification would be implemented at once :-) I recall a kind of agreement with Adriano that framing could be postponed.
Commented by: @pmakowski
framing could be postponed, but it have to be indicated somewhere or another ticket or sub-ticket have to be set for that, just to be clear about what we have or not
Commented by: @pmakowski
Standard say : OVER {window_name|(window_specification)} window_specification ::= [window_name][partitioning][ordering][framing]
so, according to the standard, you can write : select emp_no, dept_no, salary, avg(salary) over (partition by dept_no) from employee;
or you can use an explicit WINDOW clause
select emp_no, dept_no, salary, avg(salary) over w from employee WINDOW w as (partition by dept_no);
but now it returns : Statement failed, SQLSTATE = 42000 Dynamic SQL Error -SQL error code = -104 -Token unknown - line 1, column 50 -w
advantage of explicit WINDOW clause : window has a name, which can be used by multiple window table function invocations in the SELECT clause
Commented by: @sim1984
Please add a window frame clause to Firebird 4.
As far as I see, only sub-task #2058 (aka CORE-5338) remains not implemented. Do I get it right? Any plans about it?
