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### Running Aggregate Functions

Running aggregate functions are similar to functional aggregates in that they take a set of records as input, but instead of outputting the single aggregate for the entire set of records, they output the aggregate based on records encountered so far.

This section describes the running aggregate functions supported by the Oracle BI Server.

#### Mavg

Calculates a moving average (mean) for the last n rows of data in the result set, inclusive of the current row.

Syntax:

MAVG (n_expression, n)

where:

 n_expression Any expression that evaluates to a numerical value. n Any positive integer. Represents the average of the last n rows of data.

The MAVG function resets its values for each group in the query, according to the rules outlined in Display Function Reset Behavior.

The average for the first row is equal to the numeric expression for the first row. The average for the second row is calculated by taking the average of the first two rows of data. The average for the third row is calculated by taking the average of the first three rows of data, and so on until you reach the nth row, where the average is calculated based on the last n rows of data.

#### MSUM

This function calculates a moving sum for the last n rows of data, inclusive of the current row.

The sum for the first row is equal to the numeric expression for the first row. The sum for the second row is calculated by taking the sum of the first two rows of data. The sum for the third row is calculated by taking the sum of the first three rows of data, and so on. When the nth row is reached, the sum is calculated based on the last n rows of data.

This function resets its values for each group in the query according to the rules described in Display Function Reset Behavior.

Syntax:

MSUM (n_expression, n)

Where:

 n_expression Any expression that evaluates to a numerical value. n Any positive integer. Represents the sum of the last n rows of data.

Example:

The following example shows a query that uses the MSUM function and the query results.

select month, revenue, MSUM(revenue, 3) as 3_MO_SUM from sales_subject_area

 MONTH REVENUE 3_MO_SUM JAN 100.00 100.00 FEB 200.00 300.00 MAR 100.00 400.00 APRIL 100.00 400.00 MAY 300.00 500.00 JUNE 400.00 800.00 JULY 500.00 1200.00 AUG 500.00 1400.00 SEPT 500.00 1500.00 OCT 300.00 1300.00 NOV 200.00 1000.00 DEC 100.00 600.00

#### RSUM

This function calculates a running sum based on records encountered so far. The sum for the first row is equal to the numeric expression for the first row. The sum for the second row is calculated by taking the sum of the first two rows of data. The sum for the third row is calculated by taking the sum of the first three rows of data, and so on.

This function resets its values for each group in the query according to the rules described in Display Function Reset Behavior.

Syntax:

RSUM (n_expression)

Where:

 n_expression Any expression that evaluates to a numerical value.

Example:

The following example shows a query that uses the RSUM function and the query results.

select month, revenue, RSUM(revenue) as RUNNING_SUM from sales_subject_area

 MONTH REVENUE RUNNING_SUM JAN 100.00 100.00 FEB 200.00 300.00 MAR 100.00 400.00 APRIL 100.00 500.00 MAY 300.00 800.00 JUNE 400.00 1200.00 JULY 500.00 1700.00 AUG 500.00 2200.00 SEPT 500.00 2700.00 OCT 300.00 3000.00 NOV 200.00 3200.00 DEC 100.00 3300.00

#### RCOUNT

This function takes a set of records as input and counts the number of records encountered so far.

This function resets its values for each group in the query according to the rules described in Display Function Reset Behavior.

Syntax:

RCOUNT (Expr)

Where:

 Expr An expression of any data type.

Example:

The following example shows a query that uses the RCOUNT function and the query results.

select month, profit, RCOUNT(profit) from sales_subject_area where profit > 200.

 MONTH PROFIT RCOUNT (profit MAY 300.00 2 JUNE 400.00 3 JULY 500.00 4 AUG 500.00 5 SEPT 500.00 6 OCT 300.00 7

#### RMAX

This function takes a set of records as input and shows the maximum value based on records encountered so far. The specified data type must be one that can be ordered.

This function resets its values for each group in the query according to the rules described in Display Function Reset Behavior.

Syntax:

RMAX (expression)

Where:

 expression An expression of any data type. The data type must be one that has an associated sort order.

Example:

The following example shows a query that uses the RMAX function and the query results.

select month, profit, RMAX(profit) from sales_subject_area

 MONTH PROFIT RMAX (profit) JAN 100.00 100.00 FEB 200.00 200.00 MAR 100.00 200.00 APRIL 100.00 200.00 MAY 300.00 300.00 JUNE 400.00 400.00 JULY 500.00 500.00 AUG 500.00 500.00 SEPT 500.00 500.00 OCT 300.00 500.00 NOV 200.00 500.00 DEC 100.00 500.00

#### RMIN

This function takes a set of records as input and shows the minimum value based on records encountered so far. The specified data type must be one that can be ordered.

This function resets its values for each group in the query according to the rules described in Display Function Reset Behavior.

Syntax:

RMIN (expression)

Where:

 expression An expression of any data type. The data type must be one that has an associated sort order.

Example:

The following example shows a query that uses the RMIN function and the query results.

select month, profit, RMIN(profit) from sales_subject_area

 MONTH PROFIT RMIN (profit) JAN 400.00 400.00 FEB 200.00 200.00 MAR 100.00 100.00 APRIL 100.00 100.00 MAY 300.00 100.00 JUNE 400.00 100.00 JULY 500.00 100.00 AUG 500.00 100.00 SEPT 500.00 100.00 OCT 300.00 100.00 NOV 200.00 100.00 DEC 100.00 100.00