Categorize built-in functions
Transact-SQL includes many built-in functions, ranging from functions that perform data type conversion, to functions that aggregate and analyze groups of rows.
Functions in T-SQL can be categorized as follows:
Function Category
Description
Scalar
Operate on a single row, return a single value.
Logical
Compare multiple values to determine a single output.
Ranking
Operate on a partition (set) of rows.
Rowset
Return a virtual table that can be used in a FROM clause in a T-SQL statement.
Aggregate
Take one or more input values, return a single summarizing value.