diff --git a/packages/malloy/src/model/malloy_query.ts b/packages/malloy/src/model/malloy_query.ts
index f8fc915f4..be20f3fed 100644
--- a/packages/malloy/src/model/malloy_query.ts
+++ b/packages/malloy/src/model/malloy_query.ts
@@ -1183,13 +1183,13 @@ class QueryFieldDistinctKey extends QueryAtomicField {
       return this.parent.dialect.concat(
         parentKey || '', // shouldn't have to do this...
         "'x'",
-        this.parent.dialect.sqlFieldReference(
+        `(${this.parent.dialect.sqlFieldReference(
           this.parent.getIdentifier(),
           '__row_id',
           'string',
           true,
           false
-        )
+        )})`
       );
     } else {
       // return this.parent.getIdentifier() + "." + "__distinct_key";