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new 014868a0d45 [SPARK-39707][SQL][DOCS] Add SQL reference for aggregate
functions
014868a0d45 is described below
commit 014868a0d455cab8e522da51fe876541166035bc
Author: Jiaan Geng <[email protected]>
AuthorDate: Tue Jul 12 10:05:56 2022 -0700
[SPARK-39707][SQL][DOCS] Add SQL reference for aggregate functions
### What changes were proposed in this pull request?
Currently, Spark have a lot of built-in aggregate functions.
But the SQL Reference cannot find these aggregate functions directly and
cannot describe the special syntax for PERCENTILE_CONT and PERCENTILE_DISC.
### Why are the changes needed?
Add SQL reference for aggregate functions
### Does this PR introduce _any_ user-facing change?
'Yes'.
Users can find these aggregate functions directly and the special syntax
for PERCENTILE_CONT and PERCENTILE_DISC.
Before this PR, the part 'Data Retrieval Statements' of 'SQL Syntax' show
below.
After this PR, the part 'Data Retrieval Statements' of 'SQL Syntax' show
below.
The page 'Aggregate Functions' show below.
### How was this patch tested?
N/A
Closes #37116 from beliefer/SPARK-39707.
Authored-by: Jiaan Geng <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>
---
docs/sql-ref-syntax-qry-select-aggregate.md | 141 ++++++++++++++++++++++++++++
docs/sql-ref-syntax.md | 1 +
2 files changed, 142 insertions(+)
diff --git a/docs/sql-ref-syntax-qry-select-aggregate.md
b/docs/sql-ref-syntax-qry-select-aggregate.md
new file mode 100644
index 00000000000..e0e294cc50c
--- /dev/null
+++ b/docs/sql-ref-syntax-qry-select-aggregate.md
@@ -0,0 +1,141 @@
+---
+layout: global
+title: Aggregate Functions
+displayTitle: Aggregate Functions
+license: |
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+---
+
+### Description
+
+Aggregate functions operate on values across rows to perform mathematical
calculations such as sum, average, counting, minimum/maximum values, standard
deviation, and estimation, as well as some non-mathematical operations.
+
+### Syntax
+
+```sql
+aggregate_function(input1 [, input2, ...]) FILTER (WHERE boolean_expression)
+```
+
+### Parameters
+
+* **aggregate_function**
+
+ Please refer to the [Built-in Aggregation
Functions](sql-ref-functions-builtin.html#aggregate-functions) document for a
complete list of Spark aggregate functions.
+
+* **boolean_expression**
+
+ Specifies any expression that evaluates to a result type boolean. Two or
more expressions may be combined together using the logical operators ( AND, OR
).
+
+### Examples
+
+Please refer to the [Built-in Aggregation
Functions](sql-ref-functions-builtin.html#aggregate-functions) document for all
the examples of Spark aggregate functions.
+
+### Ordered-Set Aggregate Functions
+
+These aggregate Functions use different syntax than the other aggregate
functions so that to specify an expression (typically a column name) by which
to order the values.
+
+#### Syntax
+
+```sql
+{ PERCENTILE_CONT | PERCENTILE_DISC }(percentile) WITHIN GROUP (ORDER BY {
order_by_expression [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [ , ... ] })
FILTER (WHERE boolean_expression)
+```
+
+#### Parameters
+
+* **percentile**
+
+ The percentile of the value that you want to find. The percentile must be
a constant between 0.0 and 1.0.
+
+* **order_by_expression**
+
+ The expression (typically a column name) by which to order the values
before aggregating them.
+
+* **boolean_expression**
+
+ Specifies any expression that evaluates to a result type boolean. Two or
more expressions may be combined together using the logical operators ( AND, OR
).
+
+#### Examples
+
+```sql
+CREATE OR REPLACE TEMPORARY VIEW basic_pays AS SELECT * FROM VALUES
+('Diane Murphy','Accounting',8435),
+('Mary Patterson','Accounting',9998),
+('Jeff Firrelli','Accounting',8992),
+('William Patterson','Accounting',8870),
+('Gerard Bondur','Accounting',11472),
+('Anthony Bow','Accounting',6627),
+('Leslie Jennings','IT',8113),
+('Leslie Thompson','IT',5186),
+('Julie Firrelli','Sales',9181),
+('Steve Patterson','Sales',9441),
+('Foon Yue Tseng','Sales',6660),
+('George Vanauf','Sales',10563),
+('Loui Bondur','SCM',10449),
+('Gerard Hernandez','SCM',6949),
+('Pamela Castillo','SCM',11303),
+('Larry Bott','SCM',11798),
+('Barry Jones','SCM',10586)
+AS basic_pays(employee_name, department, salary);
+
+SELECT * FROM basic_pays;
++-----------------+----------+------+
+| employee_name|department|salary|
++-----------------+----------+------+
+| Anthony Bow|Accounting| 6627|
+| Barry Jones| SCM| 10586|
+| Diane Murphy|Accounting| 8435|
+| Foon Yue Tseng| Sales| 6660|
+| George Vanauf| Sales| 10563|
+| Gerard Bondur|Accounting| 11472|
+| Gerard Hernandez| SCM| 6949|
+| Jeff Firrelli|Accounting| 8992|
+| Julie Firrelli| Sales| 9181|
+| Larry Bott| SCM| 11798|
+| Leslie Jennings| IT| 8113|
+| Leslie Thompson| IT| 5186|
+| Loui Bondur| SCM| 10449|
+| Mary Patterson|Accounting| 9998|
+| Pamela Castillo| SCM| 11303|
+| Steve Patterson| Sales| 9441|
+|William Patterson|Accounting| 8870|
++-----------------+----------+------+
+
+SELECT
+ department,
+ percentile_cont(0.25) WITHIN GROUP (ORDER BY salary) AS pc1,
+ percentile_cont(0.25) WITHIN GROUP (ORDER BY salary) FILTER (WHERE
employee_name LIKE '%Bo%') AS pc2,
+ percentile_cont(0.25) WITHIN GROUP (ORDER BY salary DESC) AS pc3,
+ percentile_cont(0.25) WITHIN GROUP (ORDER BY salary DESC) FILTER (WHERE
employee_name LIKE '%Bo%') AS pc4,
+ percentile_disc(0.25) WITHIN GROUP (ORDER BY salary) AS pd1,
+ percentile_disc(0.25) WITHIN GROUP (ORDER BY salary) FILTER (WHERE
employee_name LIKE '%Bo%') AS pd2,
+ percentile_disc(0.25) WITHIN GROUP (ORDER BY salary DESC) AS pd3,
+ percentile_disc(0.25) WITHIN GROUP (ORDER BY salary DESC) FILTER (WHERE
employee_name LIKE '%Bo%') AS pd4
+FROM basic_pays
+GROUP BY department
+ORDER BY department;
++----------+-------+--------+-------+--------+-----+-----+-----+-----+
+|department| pc1| pc2| pc3| pc4| pd1| pd2| pd3| pd4|
++----------+-------+--------+-------+--------+-----+-----+-----+-----+
+|Accounting|8543.75| 7838.25| 9746.5|10260.75| 8435| 6627| 9998|11472|
+| IT|5917.75| NULL|7381.25| NULL| 5186| NULL| 8113| NULL|
+| Sales|8550.75| NULL| 9721.5| NULL| 6660| NULL|10563| NULL|
+| SCM|10449.0|10786.25|11303.0|11460.75|10449|10449|11303|11798|
++----------+-------+--------+-------+--------+-----+-----+-----+-----+
+```
+
+### Related Statements
+
+* [SELECT](sql-ref-syntax-qry-select.html)
diff --git a/docs/sql-ref-syntax.md b/docs/sql-ref-syntax.md
index b5f35f6433d..508fc67bdcb 100644
--- a/docs/sql-ref-syntax.md
+++ b/docs/sql-ref-syntax.md
@@ -76,6 +76,7 @@ ability to generate logical and physical plan for a given
query using
* [TABLESAMPLE](sql-ref-syntax-qry-select-sampling.html)
* [Table-valued Function](sql-ref-syntax-qry-select-tvf.html)
* [WHERE Clause](sql-ref-syntax-qry-select-where.html)
+ * [Aggregate Function](sql-ref-syntax-qry-select-aggregate.html)
* [Window Function](sql-ref-syntax-qry-select-window.html)
* [CASE Clause](sql-ref-syntax-qry-select-case.html)
* [PIVOT Clause](sql-ref-syntax-qry-select-pivot.html)
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