--- /dev/null
+<?php
+
+namespace Drupal\Core\Entity\Query;
+
+/**
+ * Exception thrown by Query() on unsupported query syntax.
+ *
+ * Some storage modules might not support the full range of the syntax for
+ * conditions, and will raise a QueryException when an unsupported
+ * condition was specified.
+ */
+class QueryException extends \Exception { }