Backwards-compat for multi-query table transform

* treat single-query table panels like they were before
* adjusted test cases

public/app/plugins/panel/table/specs/transformers.jest.ts

@@ -1,6 +1,6 @@
 import {transformers, transformDataToTable} from '../transformers';
 
-describe('when transforming time series table.', () => {
+describe('when transforming time series table', () => {
   var table;
 
   describe('given 2 time series', () => {
@@ -189,7 +189,7 @@ describe('when transforming time series table.', () => {
           var columns = transformers[transform].getColumns(singleQueryData);
           expect(columns[0].text).toBe('Time');
           expect(columns[1].text).toBe('Label Key 1');
-          expect(columns[2].text).toBe('Value #A');
+          expect(columns[2].text).toBe('Value');
         });
 
         it('should return the union of data columns given a multiple queries', function() {
@@ -221,7 +221,7 @@ describe('when transforming time series table.', () => {
           expect(table.columns.length).toBe(3);
           expect(table.columns[0].text).toBe('Time');
           expect(table.columns[1].text).toBe('Label Key 1');
-          expect(table.columns[2].text).toBe('Value #A');
+          expect(table.columns[2].text).toBe('Value');
         });
 
         it ('should return the union of columns for multiple queries', () => {

public/app/plugins/panel/table/transformers.ts

@@ -136,6 +136,11 @@ transformers['table'] = {
       return [];
     }
 
+    // Single query returns data columns as is
+    if (data.length === 1) {
+      return [...data[0].columns];
+    }
+
     // Track column indexes: name -> index
     const columnNames = {};
 
@@ -155,7 +160,7 @@ transformers['table'] = {
 
     // Append one value column per data set
     data.forEach((_, i) => {
-      // Value (A), Value (B),...
+      // Value #A, Value #B,...
       const text = `Value #${String.fromCharCode(65 + i)}`;
       columnNames[text] = columns.length;
       columns.push({ text });
@@ -173,6 +178,13 @@ transformers['table'] = {
       throw {message: `Result of query #${String.fromCharCode(65 + noTableIndex)} is not in table format, try using another transform.`};
     }
 
+    // Single query returns data columns and rows as is
+    if (data.length === 1) {
+      model.columns = [...data[0].columns];
+      model.rows = [...data[0].rows];
+      return;
+    }
+
     // Track column indexes: name -> index
     const columnNames = {};
     const columnIndexes = [];