Microsoft SQL Database Server Functions

There are various types of functions that can be performed on a Microsoft SQL Database Server. This course will cover a few of them.

Aggregate functions

Aggregate functions perform a calculation on a set of values and return a single value. They are allowed in the select list or the HAVING clause of a SELECT statement. You can use an aggregation in combination with the GROUP BY clause to calculate the aggregation on categories of rows. Use the OVER clause to calculate the aggregation on a specific range of value. The OVER clause cannot follow the GROUPING or GROUPING ID aggregations.

All aggregate functions are deterministic, which means they always return the same value when they run on the same input values.

Ranking functions

Ranking functions return a ranking value for each row in a partition. Depending on the function that is used, some rows might receive the same value as other rows. Ranking functions are nondeterministic.

CAST function converts an expression from one datatype to another datatype. If the conversion fails, the function will return an error. Otherwise, it will return the converted value.

CONVERT function converts an expression from one datatype to another datatype. If the conversion fails, the function will return an error. Otherwise, it will return the converted value