mssql: remove dynamic construction of metric column and other columns

This seems like a niche feature which can be solved by defining multiple queries. In the future
we'll probably add support for defining series name by alias field similar to how other datasources
have solved that, e.g. prometheus.

docker/blocks/mssql_tests/dashboard.json

@@ -88,7 +88,7 @@
   "gnetId": null,
   "graphTooltip": 0,
   "id": null,
-  "iteration": 1521458057789,
+  "iteration": 1521475806814,
   "links": [],
   "panels": [
     {
@@ -655,8 +655,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT \n  $__timeGroup(time, '$summarize') as time, \n  measurement as metric, \n  avg(valueOne) as valueOne, \n  avg(valueTwo) as valueTwo \nFROM\n  metric_values \nGROUP BY \n  $__timeGroup(time, '$summarize'), \n  measurement \nORDER BY 1",
+          "rawSql": "SELECT \n  $__timeGroup(time, '$summarize') as time, \n  measurement + ' - value one' as metric, \n  avg(valueOne) as valueOne\nFROM\n  metric_values \nGROUP BY \n  $__timeGroup(time, '$summarize'), \n  measurement \nORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT \n  $__timeGroup(time, '$summarize') as time, \n  measurement + ' - value two' as metric, \n  avg(valueTwo) as valueTwo \nFROM\n  metric_values \nGROUP BY \n  $__timeGroup(time, '$summarize'), \n  measurement \nORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -819,8 +825,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value two' as metric, valueTwo FROM metric_values ORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -983,8 +995,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value two' as metric, valueTwo FROM metric_values ORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -1147,8 +1165,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value two' as metric, valueTwo FROM metric_values ORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -1309,8 +1333,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value two' as metric, valueTwo FROM metric_values ORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -1476,8 +1506,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value two' as metric, valueTwo FROM metric_values ORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -1643,8 +1679,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value two' as metric, valueTwo FROM metric_values ORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -1810,8 +1852,14 @@
         {
           "alias": "",
           "format": "time_series",
-          "rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
           "refId": "A"
+        },
+        {
+          "alias": "",
+          "format": "time_series",
+          "rawSql": "SELECT $__timeEpoch(time), measurement + ' - value two' as metric, valueTwo FROM metric_values ORDER BY 1",
+          "refId": "B"
         }
       ],
       "thresholds": [],
@@ -2024,5 +2072,5 @@
   "timezone": "",
   "title": "Microsoft SQL Server Data Source Test",
   "uid": "GlAqcPgmz",
-  "version": 33
+  "version": 35
 }

pkg/tsdb/mssql/mssql.go

@@ -214,7 +214,6 @@ func (e MssqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.
 	for rows.Next() {
 		var timestamp float64
 		var value null.Float
-		var metricColVal string
 		var metric string
 
 		if rowCount > rowLimit {
@@ -239,7 +238,7 @@ func (e MssqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.
 
 		if metricIndex >= 0 {
 			if columnValue, ok := values[metricIndex].(string); ok == true {
-				metricColVal = columnValue
+				metric = columnValue
 			} else {
 				return fmt.Errorf("Column metric must be of type CHAR, VARCHAR, NCHAR or NVARCHAR. metric column name: %s type: %s but datatype is %T", columnNames[metricIndex], columnTypes[metricIndex].DatabaseTypeName(), values[metricIndex])
 			}
@@ -260,16 +259,8 @@ func (e MssqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.
 			default:
 				return fmt.Errorf("Value column must have numeric datatype, column: %s type: %T value: %v", col, columnValue, columnValue)
 			}
-
-			// construct the metric name
-			// if there is more than 3 columns (more than one value) and there is
-			// a metric column, join them to make the metric name
 			if metricIndex == -1 {
 				metric = col
-			} else if len(columnNames) > 3 {
-				metric = metricColVal + " - " + col
-			} else {
-				metric = metricColVal
 			}
 
 			series, exist := pointsBySeries[metric]

pkg/tsdb/mssql/mssql_test.go

@@ -364,7 +364,7 @@ func TestMSSQL(t *testing.T) {
 					Queries: []*tsdb.Query{
 						{
 							Model: simplejson.NewFromAny(map[string]interface{}{
-								"rawSql": "SELECT $__timeEpoch(time), measurement as metric, valueOne, valueTwo FROM metric_values ORDER BY 1",
+								"rawSql": "SELECT $__timeEpoch(time), measurement + ' - value one' as metric, valueOne FROM metric_values ORDER BY 1",
 								"format": "time_series",
 							}),
 							RefId: "A",
@@ -377,11 +377,9 @@ func TestMSSQL(t *testing.T) {
 				So(err, ShouldBeNil)
 				So(queryResult.Error, ShouldBeNil)
 
-				So(len(queryResult.Series), ShouldEqual, 4)
-				So(queryResult.Series[0].Name, ShouldEqual, "Metric A - valueOne")
-				So(queryResult.Series[1].Name, ShouldEqual, "Metric A - valueTwo")
-				So(queryResult.Series[2].Name, ShouldEqual, "Metric B - valueOne")
-				So(queryResult.Series[3].Name, ShouldEqual, "Metric B - valueTwo")
+				So(len(queryResult.Series), ShouldEqual, 2)
+				So(queryResult.Series[0].Name, ShouldEqual, "Metric A - value one")
+				So(queryResult.Series[1].Name, ShouldEqual, "Metric B - value one")
 			})
 
 			Convey("When doing a metric query grouping by time should return correct series", func() {