Types of aggregate calculations
The aggregate calculations you can perform on a column depend on the type of data in the column. You can perform functions only on numeric data, that enable a mathematical calculation, such as SUM and AVERAGE.
The most common aggregate functions used for string data are Count and Count Value. Count returns the number of values in a column, including duplicate values. Count Value returns the number of distinct values in the column. You can use Count Value, for example, on a customer name column to get a count of the number of customers.
For date-and-time data, you can use the MIN and MAX functions to get the earliest and the latest date, respectively, from an order date column.
For a description of the aggregate functions available, see Functions and operators.

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