diff --git a/sql.pegjs b/sql.pegjs
index 5611ca8..8aa575c 100644
--- a/sql.pegjs
+++ b/sql.pegjs
@@ -668,7 +668,7 @@ additive_expr
     }
 
 additive_operator
-  = "+" / "-"
+  = "+" / "-" / "||"
 
 multiplicative_expr
   = head:primary