MySQL aggregate function

MySQL aggregate functions are commonly used with five SUM COUNT AVG Min/max

AVG ([DISTINCT] expr)
Returns the average of expr. The DISTINCT option can be used to return the average of different values of expr.
SELECT Gender, AVG (age) from student
GROUP by gender;

COUNT (expr)
Returns the number of non-null values in the row retrieved by the SELECT statement.
SELECT COUNT (*) from student; --Returns the number of rows retrieved, regardless of whether they contain null values

SELECT COUNT (name) from student; --Returns the non-null value of the row retrieved by the SELECT statement
The number

MIN ([DISTINCT] expr), MAX ([DISTINCT] expr)
Returns the minimum and maximum values for expr
SELECT MIN (age), MAX (age) from student;

SUM ([DISTINCT] expr)
Returns the total number of expr
SELECT SUM (age) from student;

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MySQL aggregate function