Aggregate functions perform a calculation on a set of values, and returns a single value. MIN, MAX, and SUM are frequently used aggregate functions.
An aggregate function performs a calculation on a set of values, and returns a single value.
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Except for
COUNT(*), aggregate functions ignore null values. -
MAX returns NULL when there is no row to select. MAX ignores any null values.
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Aggregate functions are often used with the GROUP BY clause of the SELECT statement.
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All aggregate functions are deterministic. In other words, aggregate functions return the same value every time that they are called with a specific set of input values.
Use aggregate functions as expressions only in the following situations:
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The select list of a
SELECTstatement (either a subquery or an outer query). -
A
HAVINGclause.
For more details seehttps://learn.microsoft.com/en-us/sql/t-sql/functions/aggregate-functions-transact-sql?view=sql-server-ver16
MAX returns NULL when there is no row to select.
MAX ignores any null values.
For more details see https://learn.microsoft.com/en-us/sql/t-sql/functions/max-transact-sql?source=recommendations&view=sql-server-ver16