TABLEAVG Function
Syntax
Arguments
- tablename
The full drive, path, name, and extension of the table. If you omit the drive, path, and extension, Alpha Anywhere searches the directory of the current table.
- filter
A character filter expression that evaluates to a logical value. Selects records to average.
- field
An expression based on numeric or exponent numeric field(s) in the Lookup_Table.
Description
Returns the average value for a field in records of a specified table.
Discussion
Searches the specified Lookup_Table for one or more records that satisfy the specified Filter, and returns the average of the values contained in the Lookup_Expression. The Filter must return a logical value, either True (.T.) or False (.F.). For example, to choose all of the records in a table, use the logical constant ".T." as a filter. To choose only the records where the STATE field is equal to TN, use the filter "STATE = 'TN'". Note that the entire filter is always in quotations, and the character value, TN, is in single quotes. NOTE: If no records satisfy the filter, Alpha Anywhere returns a zero value.
Assume that a department purchasing table (PURCHASE) contains the following records:
- PURCHASE TABLE
- >
- MANAGER
- COST, BILL_DATE, and PAID_UP
- ANDRY
18500.00 01/01/2003 T
- BROWN
49.95 02/01/2003 T
- BROWN
12.99 04/01/2003 F
- FARLEY
7995.00 03/01/2003 F
- FARLEY
142.16 04/10/2003 T
- FARLEY
423.00 05/10/2003 F
Note : for detailed explanations of the filter expressions used in these examples, see TABLECOUNT().
All Records
The following expression returns the average of the values in the Cost field for all records in the Purchase table.
? TABLEAVG("PURCHASE.DBF", ".T.", "COST") = 4520.516667
Filter Using a Specific Character String
The following expression returns the average of the values in the Cost field for all records in the Purchase table where "Brown" is the manager:
? TABLEAVG("PURCHASE.DBF", "MANAGER = 'BROWN'", "COST") = 31.47
Filter Using a Character Variable
The following expression returns the average of the values in the Cost field for all records in the Purchase table where the manager matches the character string previously assigned to the variable vManager.
? TABLEAVG("PURCHASE.DBF","Manager = '" + vManager + "' ", "COST") = 2853.386667 'if vManager is "FARLEY"
Filter Using a Specific Number
The following expression returns the average of the values in the Cost field for all records in the Purchase table where the Cost is greater than 1000.00.
? TABLEAVG("PURCHASE.DBF", "Cost > 1000.00", "COST") = 13247.50
Filter Using Numeric Variable
The following expression returns the average of the values in the Cost field for all records in the Purchase table where the Cost is greater than whatever amount has been previously assigned to the numeric variable vCost.
? TABLEAVG("PURCHASE.DBF", "Cost > " + vCost, "COST") = 13247.50 ' if vCost = 1000.00
Filter Using a Specific Date Value
The following expression returns the average of the values in the Cost field for all records in the Purchase table where the Bill_Date is equal to or later than January 1, 2003.
? TABLEAVG("PURCHASE.DBF", "BILL_DATE >= {01/01/2003}", "COST") = 4520.516667
Filter Using Date Variables
The following expression returns the average of the values in the Cost field for all records in the Purchase table where the Bill_Date is equal to or later than the date previously assigned to vBeginDate AND equal to or later than the date previously assigned to vEndDate.
? TABLEAVG("PURCHASE.DBF","BETWEEN(BILL_DATE,{"+DTOC(vBeginDate)+"},{"+DTOC(vEndDate)+"})","COST") = 77.575000 ' if vBeginDate is 04/01/2003 and vEndDate is 04/30/2003
Filter Using Logical Variables
The following expression returns the average of the values in the Cost field for all records in the Purchase table where Paid_Up is true:
? TABLEAVG("PURCHASE.DBF", "PAID_UP", "COST") = 6230.703333
While this expression averages the values in the Cost field for all records in the Purchase table where Paid_Up is not true:
? TABLEAVG("PURCHASE.DBF", ".NOT. PAID_UP", "COST") = 2810.330000
Thanks to
Tom Cone
See Also