QueryFilter()

This function creates a new Query that returns all rows from an query that match the given filter.

QueryFilter( query=query, filter=function, parallel=boolean, maxThreads=number );

Returns: Query

Argument Description Default
query
query, required

query to filter entries from

filter
function, required

A function/closure that implements the following constructor

function(struct row[, number rowNumber, query query]) { return true/false; }

for best performance, use scoped variables, like arguments.row, instead of just row

parallel
boolean, optional

execute closures parallel

maxThreads
number, optional

maximum number of threads executed, ignored when argument "parallel" is set to false

Alias: maxThreadCount

20

Examples

people = QueryNew( "name,dob,age", "varchar,date,int", [
    [ "Susi", CreateDate( 1970, 1, 1 ), 0 ],
    [ "Urs" , CreateDate( 1995, 1, 1 ), 0 ],
    [ "Fred", CreateDate( 1960, 1, 1 ), 0 ],
    [ "Jim" , CreateDate( 1988, 1, 1 ), 0 ]
]);
Dump( var=people, label="people - original query" );
/* Output:
| name | dob                 | age |
------------------------------------
| Susi | 1970-01-01 00:00:00 | 0   |
| Urs  | 1995-01-01 00:00:00 | 0   |
| Fred | 1960-01-01 00:00:00 | 0   |
| Jim  | 1988-01-01 00:00:00 | 0   |
*/
//filter - older than 21
qryPeopleOldEnough = people.filter(function(row, rowNumber, qryData){
    return DateDiff('yyyy', row.dob, Now()) > 21
});
dump(var=qryPeopleOldEnough, label='qryPeopleOldEnough - older than 21');
/* Output:
| name | dob                 | age |
------------------------------------
| Susi | 1970-01-01 00:00:00 | 0   |
| Fred | 1960-01-01 00:00:00 | 0   |
| Jim  | 1988-01-01 00:00:00 | 0   |
*/
<cfscript>
	q = QueryNew("name, description");
	loop times=3 {
		getFunctionList().each(function(f){
			var fd = getFunctionData(arguments.f);
			var r =QueryAddRow(q);
			QuerySetCell(q,"name", fd.name, r);
			QuerySetCell(q,"description", fd.description, r);
		});
	}
	dump(var=q.recordcount,
	    label="demo data set size");
	s = "the";
</cfscript>
<cftimer type="outline" label="Query of Query">
	<cfquery dbtype="query" name="q1">
		select 	name, description
		from 	q
		where 	description like <cfqueryparam value='%#s#%' cfsqltype="varchar">
	</cfquery>
</cftimer>
<cfdump var=#q1.recordcount#>
<cftimer type="outline" label="query.filter() with scoped variables">
	<cfscript>
		q2 = q.filter(function(row){
			return (arguments.row.description contains s);
		});
	</cfscript>
</cftimer>
<cfdump var=#q2.recordcount#>
<cftimer type="outline" label="query.filter() without unscoped variables">
	<cfscript>
		q3 = q.filter(function(row){
			return (row.description contains s);
		});
	</cfscript>
</cftimer>
<cfdump var=#q3.recordcount#>

See also