containment of word in metadata field
diff --git a/src/main/antlr/CollectionQuery.g4 b/src/main/antlr/CollectionQuery.g4
index bf9422f..5949b73 100644
--- a/src/main/antlr/CollectionQuery.g4
+++ b/src/main/antlr/CollectionQuery.g4
@@ -83,7 +83,7 @@
 ;
 
 operator
-:	(NEG? EQ) | LT | GT | LEQ | GEQ;
+:	(NEG? EQ) | LT | GT | LEQ | GEQ | TILDE;
 
 expr
 : meta