basic-math

Counting Results

To count rows you can use the COUNT() function.

SELECT COUNT(*) FROM <table>;

To count unique entries use the DISTINCT keyword too:

SELECT COUNT(DISTINCT <column>) FROM <table>;

To count aggregated rows with common values use the GROUP BY keywords:

SELECT COUNT(<column>) FROM <table> GROUP BY <column with common value>;

Obtaining Totals

To total up numeric columns use the SUM() function.

SELECT SUM(<numeric column) FROM <table>;
SELECT SUM(<numeric column) AS <alias> FROM <table>
                                       GROUP BY <another column>
                                       HAVING <alias> <operator> <value>;

Calculating Averages

To get the average value of a numeric column use the AVG() function.

SELECT AVG(<numeric column>) FROM <table>;
SELECT AVG(<numeric column>) FROM <table> GROUP BY <other column>;

Finding the Maximum and Minimum Values

To get the maximum value of a numeric column use the MAX() function.

SELECT MAX(<numeric column>) FROM <table>;
SELECT MAX(<numeric column>) FROM <table> GROUP BY <other column>;

To get the minimum value of a numeric column use the MIN() function.

SELECT MIN(<numeric column>) FROM <table>;
SELECT MIN(<numeric column>) FROM <table> GROUP BY <other column>;

Mathematical Operators

• * Multiply

• / Divide

• + Add

• - Subtract

SELECT <numeric column> <mathematical operator> <numeric value> FROM <table>;