diff --git a/core/lib/Drupal/Core/Database/Query/Merge.php b/core/lib/Drupal/Core/Database/Query/Merge.php
index ee0406a..3d1b16c 100644
--- a/core/lib/Drupal/Core/Database/Query/Merge.php
+++ b/core/lib/Drupal/Core/Database/Query/Merge.php
@@ -403,42 +403,53 @@ public function __toString() {
   }
 
   public function execute() {
-    if (!count($this->condition)) {
-      throw new InvalidMergeQueryException(t('Invalid merge query: no conditions'));
-    }
-    $select = $this->connection->select($this->conditionTable)
-      ->condition($this->condition);
-    $select->addExpression('1');
-    if (!$select->execute()->fetchField()) {
-      try {
-        $insert = $this->connection->insert($this->table)->fields($this->insertFields);
-        if ($this->defaultFields) {
-          $insert->useDefaults($this->defaultFields);
+    try {
+      if (!count($this->condition)) {
+        throw new InvalidMergeQueryException(t('Invalid merge query: no conditions'));
+      }
+      $select = $this->connection->select($this->conditionTable)
+        ->condition($this->condition);
+      $select->addExpression('1');
+      if (!$select->execute()->fetchField()) {
+        try {
+          $insert = $this->connection->insert($this->table)->fields($this->insertFields);
+          if ($this->defaultFields) {
+            $insert->useDefaults($this->defaultFields);
+          }
+          $insert->execute();
+          return self::STATUS_INSERT;
+        }
+        catch (IntegrityConstraintViolationException $e) {
+          // The insert query failed, maybe it's because a racing insert query
+          // beat us in inserting the same row. Retry the select query, if it
+          // returns a row, ignore the error and continue with the update
+          // query below.
+          if (!$select->execute()->fetchField()) {
+            throw $e;
+          }
         }
-        $insert->execute();
-        return self::STATUS_INSERT;
       }
-      catch (IntegrityConstraintViolationException $e) {
-        // The insert query failed, maybe it's because a racing insert query
-        // beat us in inserting the same row. Retry the select query, if it
-        // returns a row, ignore the error and continue with the update
-        // query below.
-        if (!$select->execute()->fetchField()) {
-          throw $e;
+      if ($this->needsUpdate) {
+        $update = $this->connection->update($this->table)
+          ->fields($this->updateFields)
+          ->condition($this->condition);
+        if ($this->expressionFields) {
+          foreach ($this->expressionFields as $field => $data) {
+            $update->expression($field, $data['expression'], $data['arguments']);
+          }
         }
+        $update->execute();
+        return self::STATUS_UPDATE;
       }
     }
-    if ($this->needsUpdate) {
-      $update = $this->connection->update($this->table)
-        ->fields($this->updateFields)
-        ->condition($this->condition);
-      if ($this->expressionFields) {
-        foreach ($this->expressionFields as $field => $data) {
-          $update->expression($field, $data['expression'], $data['arguments']);
-        }
+    catch (\Exception $e) {
+      // If throw_exception is not set at all, we assume that exceptions are wanted
+      if (!isset($this->queryOptions['throw_exception']) || $this->queryOptions['throw_exception']) {
+        throw $e;
       }
-      $update->execute();
-      return self::STATUS_UPDATE;
+      else {
+        return NULL;
+      }    
     }
   }
 }
diff --git a/core/lib/Drupal/Core/Database/Query/Select.php b/core/lib/Drupal/Core/Database/Query/Select.php
index 1bfe9a0..e5eeaf2 100644
--- a/core/lib/Drupal/Core/Database/Query/Select.php
+++ b/core/lib/Drupal/Core/Database/Query/Select.php
@@ -589,7 +589,7 @@ public function groupBy($field) {
   public function countQuery() {
     $count = $this->prepareCountQuery();
 
-    $query = $this->connection->select($count);
+    $query = $this->connection->select($count, NULL, $this->queryOptions);
     $query->addExpression('COUNT(*)');
 
     return $query;
diff --git a/core/modules/system/lib/Drupal/system/Tests/Database/MergeTest.php b/core/modules/system/lib/Drupal/system/Tests/Database/MergeTest.php
index d5d6909..987035d 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Database/MergeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Database/MergeTest.php
@@ -208,6 +208,23 @@ function testMergeUpdateWithoutUpdate() {
    */
   function testInvalidMerge() {
     try {
+      // This query should die because there is no key field specified,
+      // but without exception, because of 'throw_exception' option.
+      $options['throw_exception'] = FALSE;
+      db_merge('test_people', $options)
+        ->fields(array(
+          'age' => 31,
+          'name' => 'Tiffany',
+        ))
+        ->execute();
+      $this->pass('$options[\'throw_exception\'] is FALSE, no InvalidMergeQueryException thrown.');
+    }
+    catch (InvalidMergeQueryException $e) {
+      $this->fail('$options[\'throw_exception\'] is FALSE, but InvalidMergeQueryException thrown for invalid query.');
+      return;
+    }
+
+    try {
       // This query should die because there is no key field specified.
       db_merge('test_people')
         ->fields(array(
diff --git a/core/modules/system/lib/Drupal/system/Tests/Database/SelectTest.php b/core/modules/system/lib/Drupal/system/Tests/Database/SelectTest.php
index 85787b8..6e157ee 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Database/SelectTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Database/SelectTest.php
@@ -376,4 +376,39 @@ function testSelectDuplicateAlias() {
     $alias2 = $query->addField('t', 'age', 'the_alias');
     $this->assertNotIdentical($alias1, $alias2, 'Duplicate aliases are renamed.');
   }
+
+  /**
+   * Tests that an invalid merge query throws an exception.
+   */
+  function testInvalidSelectCount() {
+    try {
+      // This query should die because table doesn't exists,
+      // but without exception, because of 'throw_exception' option.
+      $options['throw_exception'] = FALSE;
+      db_select('some_table_that_doesnt_exist', 't', $options)
+        ->fields('t')
+        ->countQuery()
+        ->execute();
+
+      $this->pass('$options[\'throw_exception\'] is FALSE, no Exception thrown.');
+    }
+    catch (\Exception $e) {
+      $this->fail('$options[\'throw_exception\'] is FALSE, but Exception thrown for invalid query.');
+      return;
+    }
+
+    try {
+      // This query should die because table doesn't exists,
+      db_select('some_table_that_doesnt_exist', 't')
+        ->fields('t')
+        ->countQuery()
+        ->execute();
+    }
+    catch (\Exception $e) {
+      $this->pass('Exception thrown for invalid query.');
+      return;
+    }
+    $this->fail('No Exception thrown');
+  }
+
 }