Disable usage column on MySQL installs

Closes #12

CHANGELOG.md

@@ -1,6 +1,7 @@
-## [Unreleased] 1.0.6
+## 1.0.6 - 2020-01-15
 ### Fixed
 - Fix issue with pgsql when usage column is enabled
+- Disable usage column on MySQL installs
 
 ## 1.0.5 - 2019-06-26
 ### Added

src/elements/db/TagQuery.php

@@ -8,6 +8,7 @@
 
 namespace ether\tagManager\elements\db;
 
+use Craft;
 use ether\tagManager\TagManager;
 use yii\db\Expression;
 
@@ -22,14 +23,17 @@ class TagQuery extends \craft\elements\db\TagQuery
 
 	protected function afterPrepare (): bool
 	{
+		if (Craft::$app->getDb()->getDriverName() === 'mysql')
+			return parent::afterPrepare();
+
 		if (!TagManager::getInstance()->getSettings()->enableUsage)
 			return parent::afterPrepare();
 
 		if (count($this->query->select) === 1 && strtoupper($this->query->select[0]) === 'COUNT(*)')
 			return parent::afterPrepare();
 
 		$getUsage = new Expression(
-			'(SELECT COUNT(*) FROM (SELECT [[r.sourceId]], [[r.sourceSiteId]] FROM {{%relations}} r WHERE [[r.targetId]] = [[elements.id]] GROUP BY [[r.sourceId]], [[r.sourceSiteId]]) as usage) as [[usage]]'
+			'(SELECT COUNT(*) FROM (SELECT [[r.sourceId]], [[r.sourceSiteId]] FROM {{%relations}} r WHERE [[r.targetId]] = [[elements.id]] GROUP BY [[r.sourceId]], [[r.sourceSiteId]]) as [[usage]]) as [[usage]]'
 		);
 
 		$this->query->addSelect(new Expression('[[subquery.usage]] as [[usage]]'));

src/templates/_settings.twig

@@ -2,8 +2,9 @@
 
 {{ forms.lightswitchField({
 	label: 'Enable Usage'|t('tag-manager'),
-	instructions: 'Will enable the usage column in the CP (has no effect on regular tag queries, may be slow on larger sites).'|t('tag-manager'),
+	instructions: '**[PostgreSQL Only]** Will enable the usage column in the CP (has no effect on regular tag queries, may be slow on larger sites).'|t('tag-manager'),
 	name: 'enableUsage',
-	on: settings.enableUsage,
+	on: craft.app.db.driverName == 'pgsql' and settings.enableUsage,
 	first: true,
+	disabled: craft.app.db.driverName == 'mysql'
 }) }}

src/translations/en/tag-manager.php

@@ -9,6 +9,6 @@
 return [
 	'Usage' => 'Usage',
 	'Enable Usage' => 'Enable Usage',
-	'Will enable the usage column in the CP (has no effect on regular tag queries, may be slow on larger sites).' =>
-		'Will enable the usage column in the CP (has no effect on regular tag queries, may be slow on larger sites).',
+	'**[PostgreSQL Only]** Will enable the usage column in the CP (has no effect on regular tag queries, may be slow on larger sites).' =>
+		'**[PostgreSQL Only]** Will enable the usage column in the CP (has no effect on regular tag queries, may be slow on larger sites).',
 ];