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QueryReduce
Last update:
May 18, 2026
Description
This function iterates over each row of a query and calls the closure function to work on the row of the query. This function reduces the query to a single value that would be returned.
Returns
The result returned by the last invocation of reduce function (with the last row).
Category
History
New in Adobe ColdFusion (2016 release)
See also
Syntax
Object QueryReduce(Object query , UDFMethod reduceFunc [, Object initialValue])Parameters
Parameter | Description |
query | (Required) The query to be iterated over. |
reduceFunc | (Required) The reduce function to be called with each row of the query. |
initialValue | (Optional) The value to be passed to reduce function for the first row. |
Example 1
<cfscript>
myQuery = queryNew("id,name,amount","Integer,Varchar,Integer",
[
{id=1,name="One",amount=15},
{id=2,name="Two",amount=18},
{id=3,name="Three",amount=32},
{id=3,name="Four",amount=35}
]);
addAges=QueryReduce(myQuery,function(sum,obj){
sum=sum+obj.amount
return sum
},0)
writeOutput("The sum of all amount is: " & addAges)
</cfscript>Example 2
<cfscript>
qoptions = {result="myresult", datasource="cfbookclub", fetchclientinfo="yes"};
sampleQuery = QueryExecute("select * from books order by bookid", [] ,qoptions);
temp = "";
titles = QueryReduce(sampleQuery, function(temp, element){
temp = temp?:"";
temp = temp & element.TITLE & " | ";
return temp;
});
writeOutput(titles);
</cfscript>The script returns a string of appended titles.
Using member function
<cfscript>
myResult=QueryExecute("SELECT * FROM EMPLOYEES",[],{datasource="cfdocexamples"});
myArray=ArrayNew(1);
// Populate myArrray with random values between 25-45
for (i=1;i<=myResult.recordcount;i++){
myArray[i]=randrange(25,45);
}
// Add column Ages and populate with values of myArray
QueryAddColumn(myResult,"Ages","integer",myArray);
// Use reduce function to calculate the average age of all persons in the recordset
// Initialize age in closure
status=myResult.reduce(function(age=0,col){
return age+col.Ages/myResult.recordcount;
});
WriteOutput(status);
</cfscript>
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