How to 'group by' a field in processwire?

[SIERRA]

Hai ,

Coding:
  <select name="eventstart" id="eventstart">

        <option value=""><?php echo $lang['select_event_start']; ?></option>

        <?php
        
        foreach( $events_pages->events->find($filter.",  sort=event_start") as $event) {?>

           <option value="<?php echo $event->event_start;?>"><?php echo $event->event_start;?></option>        

        <?php } ?>        

        </select>

It results:

But , i need result without repeated dates.how to 'groupby' event_start field in processwire ?could you please sugguest me
Thank you

[dragan]

You could probably use unique(): http://cheatsheet.processwire.com/pagearray-wirearray/getting-items/a-unique/

Either way, I would avoid doing a find() in every foreach - that's inefficient. Define a variable for the results before your foreach.

$results = $events_pages->events->find($filter.",  sort=event_start");
$unique = $results->unique();
foreach($unique as $e) // etc.

 

[Soma]

There's no group by feature in PW. WireArray->unique() doesn't work for this purpose.

Using the API you could Just build an array using WireArray->explode() and use array_unique(). Depending how large the result set is you could cache the array so it only builds the array when it expires or based on a selector.

$uniquedates = $cache->get("uniquedates", "template=basic-page", function(){
	return array_unique(wire("pages")->find("template=basic-page, sort=date")->explode("date"));
});

print_r($uniquedates);

 If the amount of entries is very large and it would take several seconds to build the array, it could make sense to use something like direct SQL query.

[bernhard]

11 minutes ago, Soma said:

If the amount of entries is very large and it would take several seconds to build the array, it could make sense to use something like direct SQL query.

It's easy using RockFinder. See the example in the docs: https://gitlab.com/baumrock/RockFinder#custom-sql-aggregations-groupings-distincts

[d'Hinnisdaël]

For most group-by-property situations, I use Fun with hooks: PageArray::groupBy.

[bernhard]

7 hours ago, d'Hinnisdaël said:

For most group-by-property situations, I use Fun with hooks: PageArray::groupBy.

Just have in mind that this method gets very slow with lots of pages.

[d'Hinnisdaël]

3 hours ago, bernhard said:

Just have in mind that this method gets very slow with lots of pages.

Good point. I've always used it conjunction with some light caching to store the results as JSON.

[KarlvonKarton]

On 8/31/2018 at 2:17 PM, bernhard said:

It's easy using RockFinder

Great module!  It is everything I needed for "group by" queries.

[pwfans]

Maybe below code can help for simple group by date for example  :

$list = $pages->find("template=event");  
$groups = array();  
foreach ($list as $item) {  
	$groups["$item->date"][] = $item->id; 
}

foreach($groups as $key => $gr){         
	echo $key."<br>";
}

 

[bernhard]

RockFinder3 has a performant and versatile SQL groupby feature: https://github.com/baumrock/RockFinder3/tree/40da7c5f087d87bc33d883add5b78cf7c546bacd#predefined-methods

[torf]

As i ran into the same Problem here is a very simple solution that only uses one loop for grouping (well it's not exactly grouping, but it looks like)

$myPages = $pages->find("template=myTemplate, sort=FieldtoGroupby, sort=title"); //select all pages and sort by field you want to group, then by sorting field
$lastgroup = "somevalueneverused";
foreach($myPages as $myPage) {
	$actualgroup = $myPage->FieldtoGroupby;
	if ($lastgroup != $actualgroup) {
		echo "<h3>".$myPage->FieldtoGroupby."</h3>";
	}
	echo "<p>".$myPage->title."</p>";
	$lastgroup = $actualgroup;
}

Downside: you only can sort your categories by the field to group by.