Fixes #2687: ActiveQuery::joinWith() has problem when the query is used twice.

framework/db/ActiveQuery.php

@@ -236,10 +236,6 @@ class ActiveQuery extends Query implements ActiveQueryInterface
 	 */
 	protected function createCommandInternal($db)
 	{
-		if (!empty($this->joinWith)) {
-			$this->buildJoinWith();
-		}
-
 		/** @var ActiveRecord $modelClass */
 		$modelClass = $this->modelClass;
 		if ($db === null) {
@@ -247,6 +243,10 @@ class ActiveQuery extends Query implements ActiveQueryInterface
 		}
 
 		if ($this->sql === null) {
+			if (!empty($this->joinWith)) {
+				$this->buildJoinWith();
+				$this->joinWith = null;    // clean it up to avoid issue https://github.com/yiisoft/yii2/issues/2687
+			}
 			list ($sql, $params) = $db->getQueryBuilder()->build($this);
 		} else {
 			$sql = $this->sql;

tests/unit/framework/db/ActiveRecordTest.php

@@ -393,6 +393,13 @@ class ActiveRecordTest extends DatabaseTestCase
 		$this->assertEquals(2, count($orders[0]->books2));
 		$this->assertEquals(0, count($orders[1]->books2));
 		$this->assertEquals(1, count($orders[2]->books2));
+
+		// join with count and query
+		$query = Order::find()->joinWith('customer');
+		$count = $query->count();
+		$this->assertEquals(3, $count);
+		$orders = $query->all();
+		$this->assertEquals(3, count($orders));
 	}
 
 	public function testJoinWithAndScope()