🛢DBMS: Aggregate Function (Definitions)

"A function that works on a set of cells to produce a single answer or set of answers, one for each subset of cells. The aggregate functions available in Transact-SQL are: average (avg), maximum (max), minimum (min), sum (sum), and count of the number of items (count)." (Karen Paulsell et al, "Sybase SQL Server: Performance and Tuning Guide", 1996)

"Include SUM, AVG, COUNT, COUNT(*), MAX, and MIN. These functions generate summary values that appear as new columns in query results. They act on the whole table or on a subset of the rows." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"Functions that calculate summary values, such as averages and sums, from the values in a particular column and return a single value for each set of rows to which the function applies. The aggregate functions are AVG, COUNT, COUNT(*), MAX, MIN, SUM, STDEV, STDEVP, VAR, and VARP. Aggregate functions can be applied either to all rows in a table, to a subset of table rows specified by a WHERE clause, or to one or more groups of table rows specified by the GROUP BY clause." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"An aggregate function performs a calculation on a column in a set of rows and returns a single value." (Anthony Sequeira & Brian Alderman, "The SQL Server 2000 Book", 2003)

"A type of function in Oracle SQL that performs a calculation or transformation across multiple rows in a table, rather than just on a single row." (Bob Bryla, "Oracle Database Foundations", 2004)

"Functions that provide summary data over sets returning a singular value." (Thomas Moore, "EXAM CRAM™ 2: Designing and Implementing Databases with SQL Server 2000 Enterprise Edition", 2005)

"A function that performs a calculation at the column level on a set of rows to return a single value. Examples of T-SQL aggregate functions include AVG, MIN, and SUM." (Marilyn Miller-White et al, "MCITP Administrator: Microsoft® SQL Server™ 2005 Optimization and Maintenance 70-444", 2007)

"A function that produces a single result based on the contents of an entire set of table rows." (S. Sumathi & S. Esakkirajan, "Fundamentals of Relational Database Management Systems", 2007)

"A function that performs a summary calculation on a series of data and returns a single value. Each aggregate function uses the Scope parameter, which defines the scope (such as grouping, data set, or data region) in which the aggregate function is performed." (Jim Joseph et al, "Microsoft SQL Server 2008 Reporting Services Unleashed", 2009)

"A SQL function - for example, AVG and SUM - that computes a variety of measures based on values in one or more numeric columns." (Jan L Harrington, "SQL Clearly Explained 3rd Ed. ", 2010)

"A function that performs a calculation on multiple values and returns a single value." (Microsoft, "SQL Server 2012 Glossary", 2012)

"A function that optionally accepts arguments and returns a single scalar value that is the result of an evaluation of a set of like values, such as those in a column within a set of one or more rows. See also function, routine." (Sybase, "Open Server Server-Library/C Reference Manual", 2019)

"A function that generates a single value from a group of values, often used with GROUP BY and HAVING clauses. Aggregate functions include AVG, COUNT, MAX, MIN, and SUM. Also known as set functions. See also scalar function." (Microsoft, "ODBC Glossary")

"A function that performs a calculation on multiple values and returns a single summary value." (Microsoft Technet)

"In a query, a function such as COUNT, AVG, or STDEV that calculates a value using all the rows in a column of a table. In writing expressions and in programming, you can use SQL aggregate functions (including the three listed above) and domain aggregate functions to determine various statistics." (Microsoft, "ADO Glossary Terms")