cloud-fan commented on code in PR #37116: URL: https://github.com/apache/spark/pull/37116#discussion_r918509777
########## docs/sql-ref-syntax-qry-select-aggregate.md: ########## @@ -0,0 +1,125 @@ +--- +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. + +### General Aggregation + +Please refer to the [Built-in Aggregation Functions](sql-ref-functions-builtin.html#aggregate-functions) document for a complete list 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. + +* **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, Review Comment: can we give some examples for simple agg functions such as count, sum? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
