{"id":1006,"date":"2018-10-21T15:58:10","date_gmt":"2018-10-21T08:58:10","guid":{"rendered":"http:\/\/www.sqlservertutorial.net\/?page_id=1006"},"modified":"2024-04-03T14:51:21","modified_gmt":"2024-04-03T07:51:21","slug":"sql-server-aggregate-functions","status":"publish","type":"page","link":"https:\/\/www.sqlservertutorial.net\/sql-server-aggregate-functions\/","title":{"rendered":"SQL Server Aggregate Functions"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn about the SQL Server aggregate functions and how to use them to calculate aggregates.<\/p>\n\n\n\n

An aggregate function operates on a set of values and returns a single value. In practice, you often use aggregate functions with the GROUP BY<\/a><\/code> clause and HAVING<\/a><\/code> clause to aggregate values within groups.<\/p>\n\n\n\n

The following table shows the most commonly used SQL Server aggregate functions:<\/p>\n\n\n\n<\/input><\/p>\n\n\n\n

Aggregate function<\/th>Description<\/th><\/tr><\/thead>
AVG<\/a><\/td>Calculate the average of non-NULL values in a set of values.<\/td><\/tr>
CHECKSUM_AGG<\/a><\/td>Calculate a checksum value based on a group of rows.<\/td><\/tr>
COUNT<\/a><\/td>Return the number of rows in a group that satisfy a condition.<\/td><\/tr>
COUNT(*)<\/a><\/td>Return the number of rows from a table, which meets a certain condition.<\/td><\/tr>
COUNT(DISTINCT)<\/a><\/td>Return the number of unique values in a column that meets a certain condition.<\/td><\/tr>
COUNT IF<\/a><\/td>Show you how to use the COUNT<\/code> function with the IIF<\/code> function to form a COUNT IF<\/code> function that returns the total number of values based on a condition.<\/td><\/tr>
COUNT_BIG<\/a><\/td>The COUNT_BIG()<\/code> function returns the number of rows (with BIGINT data type) in a group, including rows with NULL values.<\/td><\/tr>
MAX<\/a><\/td>Return the highest value (maximum) in a set of non-NULL values.<\/td><\/tr>
MIN<\/a><\/td>Return the lowest value (minimum) in a set of non-NULL values.<\/td><\/tr>
STDEV<\/a><\/td>Calculate the sample standard deviation of a set of values.<\/td><\/tr>
STDEVP<\/td>Return the population standard deviation of a set of values.<\/td><\/tr>
SUM<\/a><\/td>Return the summation of all non-NULL values in a set.<\/td><\/tr>
SUM IF<\/a><\/td>Use the SUM<\/code> function with the IIF<\/code> function to form a SUM IF<\/code> function that returns the total of values based on a condition.<\/td><\/tr>
STRING_AGG<\/a>\u00a0<\/td>Concatenate strings by a specified separator<\/td><\/tr>
VAR<\/a><\/td>Return the sample variance of a set of values.<\/td><\/tr>
VARP<\/td>Return the population variance of a set of values.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

SQL Server aggregate function syntax #<\/a><\/h2>\n\n\n\n

Here’s is the general syntax of an aggregate function:<\/p>\n\n\n

aggregate_function_name( [DISTINCT | ALL] expression)<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
In this syntax:<\/p>\n\n\n\n