MySQL aggregate functions and grouping

aggregate functions

MySQL aggregate functions retrieve a single value after performing a calculation on a set of values.

In general, aggregate functions ignore null values.

Often, aggregate functions are accompanied by the GROUP BY clause of the SELECT statement.

List of MySQL aggregate functions and a hint of what they do

AVG()

MySQL AVG() retrieves the average value of the argument.

BIT_AND()

MySQL BIT_AND() bitwise and.

BIT_OR()

MySQL BIT_OR() retrieves bitwise or.

BIT_XOR()

MySQL BIT_OR() retrieves bitwise xor.

COUNT(DISTINCT)

MySQL COUNT(DISTINCT) retrieves the count of a number of different values.

COUNT()

MySQL COUNT() retrieves a count of the number of rows returned.

GROUP_CONCAT()

MySQL GROUP_CONCAT() retrieves a concatenated string.

MAX()

MySQL MAX() retrieves the maximum value.

MIN()

MySQL BIT_OR() retrieves the minimum value.

STD()

MySQL MIN()retrieves the population standard deviation.

STDDEV_POP()

MySQL BIT_OR() retrieves the population standard deviation.

STDDEV_SAMP()

MySQL STDDEV_POP() retrieves the sample standard deviation.

STDDEV()

MySQL STDDEV() retrieves the population standard deviation.

SUM()

MySQL SUM() retrieves the sum.

VAR_POP()

MySQL VAR_POP() the population standard variance.

VAR_SAMP()

MySQL VAR_POP() the sample variance.

VARIANCE()

MySQL VAR_POP()the population standard variance.

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