diff --git a/public/app/core/utils/explore.ts b/public/app/core/utils/explore.ts
index be771c1b232..e268508b833 100644
--- a/public/app/core/utils/explore.ts
+++ b/public/app/core/utils/explore.ts
@@ -130,10 +130,15 @@ export function ensureQueries(queries?: DataQuery[]): DataQuery[] {
 }
 
 /**
- * A target is non-empty when it has keys other than refId and key.
+ * A target is non-empty when it has keys (with non-empty values) other than refId and key.
  */
 export function hasNonEmptyQuery(queries: DataQuery[]): boolean {
-  return queries.some(query => Object.keys(query).length > 2);
+  return queries.some(
+    query =>
+      Object.keys(query)
+        .map(k => query[k])
+        .filter(v => v).length > 2
+  );
 }
 
 export function calculateResultsFromQueryTransactions(
diff --git a/public/app/features/explore/Explore.tsx b/public/app/features/explore/Explore.tsx
index 71e23640bec..23a06a5acc9 100644
--- a/public/app/features/explore/Explore.tsx
+++ b/public/app/features/explore/Explore.tsx
@@ -772,6 +772,9 @@ export class Explore extends React.PureComponent<ExploreProps, ExploreState> {
   async runQueries(resultType: ResultType, queryOptions: any, resultGetter?: any) {
     const queries = [...this.modifiedQueries];
     if (!hasNonEmptyQuery(queries)) {
+      this.setState({
+        queryTransactions: [],
+      });
       return;
     }
     const { datasource } = this.state;