diff --git a/public/app/plugins/datasource/postgres/postgres_query.ts b/public/app/plugins/datasource/postgres/postgres_query.ts
index d5bdf005e8f..7e49a8a149f 100644
--- a/public/app/plugins/datasource/postgres/postgres_query.ts
+++ b/public/app/plugins/datasource/postgres/postgres_query.ts
@@ -151,11 +151,7 @@ export default class PostgresQuery {
           if (func === 'first' || func === 'last') {
             query = func + '(' + query + ',' + this.target.timeColumn + ')';
           } else {
-            if (windows) {
-              query = func + '(' + query + ' ORDER BY ' + this.target.timeColumn + ')';
-            } else {
-              query = func + '(' + query + ')';
-            }
+            query = func + '(' + query + ')';
           }
           break;
         case 'percentile':
diff --git a/public/app/plugins/datasource/postgres/specs/postgres_query.jest.ts b/public/app/plugins/datasource/postgres/specs/postgres_query.jest.ts
index c1d5400d1fa..1e2b75417da 100644
--- a/public/app/plugins/datasource/postgres/specs/postgres_query.jest.ts
+++ b/public/app/plugins/datasource/postgres/specs/postgres_query.jest.ts
@@ -98,8 +98,8 @@ describe('PostgresQuery', function() {
       { type: 'window', params: ['increase'] },
     ];
     expect(query.buildValueColumn(column)).toBe(
-      '(CASE WHEN max(v ORDER BY time) >= lag(max(v ORDER BY time)) OVER (PARTITION BY host ORDER BY time) ' +
-        'THEN max(v ORDER BY time) - lag(max(v ORDER BY time)) OVER (PARTITION BY host ORDER BY time) ELSE max(v ORDER BY time) END) AS "a"'
+      '(CASE WHEN max(v) >= lag(max(v)) OVER (PARTITION BY host ORDER BY time) ' +
+        'THEN max(v) - lag(max(v)) OVER (PARTITION BY host ORDER BY time) ELSE max(v) END) AS "a"'
     );
   });