The AVG function returns the average value of a column in a selection. NULL values are not included in the calculation. The column must be a numerical column.

AVG(colName) evaluates colName for each row in a table and returns the average.

AVG(ALL colName) evaluates colName for each non null row in a table. ALL is the default syntax.

AVG(DISTINCT colName) evaluates colName for each distinct row in a table and returns the average (duplicate values are ignored)

During join queries a colName must be fully qualified using the table name as well.

Example:

AVG(table.colName)

Example

SELECT AVG(column) FROM table;