InfluxDB: Flux: timestamp-column has to be first in dataframes (#35036) (#35053)

(cherry picked from commit 38b030e2a4)

Co-authored-by: Gábor Farkas <gabor.farkas@gmail.com>

pkg/tsdb/influxdb/flux/builder.go

@@ -167,10 +167,6 @@ func (fb *frameBuilder) Init(metadata *query.FluxTableMetadata) error {
 	dataColumns := getDataColumns(columns)
 	fb.hasUsualStartStop = hasUsualStartStop(dataColumns)
 
-	// first we store the column-info structures as pointers,
-	// because we need to modify some items in the list
-	var columnInfos []*columnInfo
-
 	for _, col := range dataColumns {
 		if col.IsGroup() {
 			fb.labels = append(fb.labels, col.Name())
@@ -191,8 +187,6 @@ func (fb *frameBuilder) Init(metadata *query.FluxTableMetadata) error {
 				isTheSingleValue: false,
 			}
 
-			columnInfos = append(columnInfos, info)
-
 			if isTimestamp {
 				timestampCols = append(timestampCols, info)
 			} else {
@@ -216,7 +210,12 @@ func (fb *frameBuilder) Init(metadata *query.FluxTableMetadata) error {
 		nonTimestampCols[0].isTheSingleValue = true
 	}
 
-	for _, colInfo := range columnInfos {
+	// grafana wants the timestamp columns first, so we add them first
+	for _, colInfo := range timestampCols {
+		fb.columns = append(fb.columns, *colInfo)
+	}
+	// then we add the non-timestamp-columns
+	for _, colInfo := range nonTimestampCols {
 		fb.columns = append(fb.columns, *colInfo)
 	}