MYSQL Tutorial Part 3

 AGGREGATE FUNCTIONS

        Aggregate functions are used to collect the values from multiple rows as input and perform some calculations. It returns a single value.

TYPES OF AGGREGATE FUNCTIONS:

1. count
2. sum
3. avg
4. max
5. min

COUNT():

• The COUNT() function counts the number of rows that matches a specified criterion.
• It returns the total number of records.
• It works for both numeric and non-numeric data types.

    Syntax

        SELECT COUNT(column_name) FROM table_name WHERE condition;

    Example
        SELECT COUNT(department) FROM Student WHERE department = 'CSE';

SUM():

• The SUM() function returns the sum of all the values in the selected column.
• It works for numeric data types only.

    Syntax

        SELECT SUM(column_name) FROM table_name WHERE condition;

    Example
        SELECT SUM(fees) FROM Student WHERE department = 'CSE';

AVG():

• The AVG() function returns the average value of a numeric column. 
• It returns the average of non-null values of the column.

    Syntax

        SELECT AVG(column_name) FROM table_name WHERE condition;

    Example
        SELECT AVG(fees) FROM Student WHERE department = 'CSE';

MIN() and MAX():

• The MIN() function returns the smallest value of the selected column.
• The MAX() function returns the largest value of the selected column.

    MIN() Syntax

        SELECT MIN(column_name) FROM table_name WHERE condition;

    MAX() Syntax

        SELECT MAX(column_name) FROM table_name WHERE condition;

    Example
        SELECT MIN(fees) AS MinFees, MAX(fees) AS MaxFees FROM Student;

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                                    Will discuss MySQL conditions in the next part. -  Part-4

Tutorial Topics:

Introduction  -  Part-1

Database Creation  -  Part-2

Aggregate Functions  - Part-3

Conditions  - Part-4

Constraints  - Part-5

Clauses  -  Part-6

Joins  -  Part-7

Tutorial Topics for examples:

Database Creation -  Part-1

Table Modifications  -  Part-2

Clauses   - Part-3

Operators  - Part-4

Joins  - Part-5