Write about Aggregate Functions in SQL.

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teamques10 ★ 68k

Aggregate functions perform a calculation on a set of values and return a single value.
Aggregate functions are frequently used with the GROUP BY clause of the SELECT statement.
All aggregate functions are deterministic. This means aggregate functions return the same value any time that they are called by using a specific set of input values.
Most Commonly used functions are as follows:

AVG() - The SQL AVG aggregate function selects the average value for certain table column. Example: SELECT AVG(Goals) FROM Players;

COUNT() - The SQL COUNT aggregate function is used to count the number of rows in a database table. Example: SELECT COUNT(*) FROM Players WHERE club = 'Chelsea';

MAX() - The SQL MAX aggregate function allows us to select the highest (maximum) value for a certain column. Example: SELECT MAX(Goals) FROM Players;

MIN() - The SQL MIN aggregate function allows us to select the lowest (minimum) value for a certain column. Example:SELECT MIN(Goals) FROM Players;

SUM() - The SQL SUM aggregate function allows selecting the total for a numeric column. Example:SELECT SUM(Goals) FROM Players;

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