Filter resources by template variable value with MODx Wayfinder

Question

I have a site that uses Wayfinder to display the latest 3 entries from an Articles blog. Now, I want to only consider those blog entries that are tagged Highlights.

My original Wayfinder call looks like this, nothing spectacular:

[[!Wayfinder? &startId=`296` &level=`1`
    &outerTpl=`emptyTpl`
    &innerTpl=``
    &rowTpl=`thumbnails_formatter`
    &ignoreHidden=`1`
    &sortBy=`menuindex`
    &sortOrder=`DESC`
    &limit=`3`
    &cacheResults=`0`
]]

as Articles tags are managed via the articlestags TV, I thought that a &where might do the trick, but with no luck yet:

&where=`[{"articlestags:LIKE":"%Highlights%"}]`

does not yield anything. As a sanity check, I tried [{"pagetitle:LIKE":"%something%"}], which worked. Obviously, the problem is that articlestags is not a column of modx_site_content, but I'm not sure about how to put the subquery.

SELECT contentid
FROM modx_site_tmplvar_contentvalues
WHERE tmplvarid=17
  AND value LIKE '%Highlights%'

Gave me the right IDs on the sql prompt, but adding it to the Wayfinder call like this gave an empty result again:

&where=`["id IN (SELECT contentid FROM modx_site_tmplvar_contentvalues WHERE tmplvarid=17 AND value LIKE '%Highlights%')"]`

Any ideas on how to achieve this? I'd like to stay with Wayfinder for consistency, but other solutions are welcome as well.

Answer 1

A little playing around led me to a solution: I needed to include the class name (not table name) when referring to the ID:

&where=`["modResource.id IN (SELECT contentid FROM modx_site_tmplvar_contentvalues WHERE tmplvarid=17 AND value LIKE '%Highlights%')"]`

a small test showed that even a simple

&where=`["id = 123"]`

does not work without modResource..

A look at wayfinder.class.php shows the following line, which seems to be the "culprit":

$c->select($this->modx->getSelectColumns('modResource','modResource'));

This method aliases the selected columns - relevant code is in xpdoobject.class.php. The first parameter is the class name, the second a table alias. The effect is that the query selects id AS modResource.id, and so on.

---

EDIT: final version of my query:

&where=`["modResource.id IN (
    SELECT val.contentid
    FROM modx_site_tmplvars AS tv
    JOIN modx_site_tmplvar_contentvalues AS val
     ON tv.id = val.tmplvarid
    WHERE tv.name = 'articlestags' AND (
        val.value = 'Highlights'
     OR val.value LIKE 'Highlights,%'
     OR val.value LIKE '%,Highlights'
     OR val.value LIKE '%,Highlights,%'
    )
)"]`

I don't claim this query is particularly efficient (I seem to recall that OR conditions are bad). Also, MODx won't work with this one if the newlines aren't stripped out. Still, I prefer to publish the query in its well-formatted form.