modify $__timeGroup macro so it can be used in select clause (#9527)

* modify $__timeGroup macro so it can be used in select clause

* fix $__interval_ms for postgres datasource

* use $__timeGroup macro in documentation

* fix annotation template query
remove title since its no longer used and add tags instead

* change __timeFilter macro to work on postgresql < 8.1 and redshift

docs/sources/features/datasources/postgres.md

@@ -48,7 +48,7 @@ Macro example | Description
 *$__timeFilter(dateColumn)* | Will be replaced by a time range filter using the specified column name. For example, *dateColumn > to_timestamp(1494410783) AND dateColumn < to_timestamp(1494497183)*
 *$__timeFrom()* | Will be replaced by the start of the currently active time selection. For example, *to_timestamp(1494410783)*
 *$__timeTo()* | Will be replaced by the end of the currently active time selection. For example, *to_timestamp(1494497183)*
-*$__timeGroup(dateColumn,'5m')* | Will be replaced by an expression usable in GROUP BY clause. For example, *(extract(epoch from "dateColumn")/extract(epoch from '5m'::interval))::int*
+*$__timeGroup(dateColumn,'5m')* | Will be replaced by an expression usable in GROUP BY clause. For example, *(extract(epoch from "dateColumn")/extract(epoch from '5m'::interval))::int*extract(epoch from '5m'::interval)*
 *$__unixEpochFilter(dateColumn)* | Will be replaced by a time range filter using the specified column name with times represented as unix timestamp. For example, *dateColumn > 1494410783 AND dateColumn < 1494497183*
 *$__unixEpochFrom()* | Will be replaced by the start of the currently active time selection as unix timestamp. For example, *1494410783*
 *$__unixEpochTo()* | Will be replaced by the end of the currently active time selection as unix timestamp. For example, *1494497183*
@@ -94,26 +94,26 @@ Example with `metric` column
 
 ```sql
 SELECT
-  min(time_date_time) as time,
+  $__timeGroup(time_date_time,'5m') as time,
   min(value_double),
   'min' as metric
 FROM test_data
 WHERE $__timeFilter(time_date_time)
-GROUP BY metric1, (extract(epoch from time_date_time)/extract(epoch from $__interval::interval))::int
-ORDER BY time asc
+GROUP BY time
+ORDER BY time
 ```
 
 Example with multiple columns:
 
 ```sql
 SELECT
-  min(time_date_time) as time,
+  $__timeGroup(time_date_time,'5m') as time,
   min(value_double) as min_value,
   max(value_double) as max_value
 FROM test_data
 WHERE $__timeFilter(time_date_time)
-GROUP BY metric1, (extract(epoch from time_date_time)/extract(epoch from $__interval::interval))::int
-ORDER BY time asc
+GROUP BY time
+ORDER BY time
 ```
 
 ## Templating

pkg/tsdb/postgres/macros.go

@@ -74,7 +74,7 @@ func (m *PostgresMacroEngine) evaluateMacro(name string, args []string) (string,
 		if len(args) == 0 {
 			return "", fmt.Errorf("missing time column argument for macro %v", name)
 		}
-		return fmt.Sprintf("%s >= to_timestamp(%d) AND %s <= to_timestamp(%d)", args[0], uint64(m.TimeRange.GetFromAsMsEpoch()/1000), args[0], uint64(m.TimeRange.GetToAsMsEpoch()/1000)), nil
+		return fmt.Sprintf("extract(epoch from %s) BETWEEN %d AND %d", args[0], uint64(m.TimeRange.GetFromAsMsEpoch()/1000), uint64(m.TimeRange.GetToAsMsEpoch()/1000)), nil
 	case "__timeFrom":
 		return fmt.Sprintf("to_timestamp(%d)", uint64(m.TimeRange.GetFromAsMsEpoch()/1000)), nil
 	case "__timeTo":
@@ -83,7 +83,7 @@ func (m *PostgresMacroEngine) evaluateMacro(name string, args []string) (string,
 		if len(args) < 2 {
 			return "", fmt.Errorf("macro %v needs time column and interval", name)
 		}
-		return fmt.Sprintf("(extract(epoch from \"%s\")/extract(epoch from %s::interval))::int", args[0], args[1]), nil
+		return fmt.Sprintf("(extract(epoch from \"%s\")/extract(epoch from %s::interval))::int*extract(epoch from %s::interval)", args[0], args[1], args[1]), nil
 	case "__unixEpochFilter":
 		if len(args) == 0 {
 			return "", fmt.Errorf("missing time column argument for macro %v", name)

pkg/tsdb/postgres/macros_test.go

@@ -30,7 +30,7 @@ func TestMacroEngine(t *testing.T) {
 			sql, err := engine.Interpolate(timeRange, "WHERE $__timeFilter(time_column)")
 			So(err, ShouldBeNil)
 
-			So(sql, ShouldEqual, "WHERE time_column >= to_timestamp(18446744066914186738) AND time_column <= to_timestamp(18446744066914187038)")
+			So(sql, ShouldEqual, "WHERE extract(epoch from time_column) BETWEEN 18446744066914186738 AND 18446744066914187038")
 		})
 
 		Convey("interpolate __timeFrom function", func() {
@@ -45,7 +45,7 @@ func TestMacroEngine(t *testing.T) {
 			sql, err := engine.Interpolate(timeRange, "GROUP BY $__timeGroup(time_column,'5m')")
 			So(err, ShouldBeNil)
 
-			So(sql, ShouldEqual, "GROUP BY (extract(epoch from \"time_column\")/extract(epoch from '5m'::interval))::int")
+			So(sql, ShouldEqual, "GROUP BY (extract(epoch from \"time_column\")/extract(epoch from '5m'::interval))::int*extract(epoch from '5m'::interval)")
 		})
 
 		Convey("interpolate __timeTo function", func() {

public/app/plugins/datasource/postgres/datasource.ts

@@ -20,6 +20,10 @@ export class PostgresDatasource {
       return '\'' + value + '\'';
     }
 
+    if (typeof value === 'number') {
+      return value.toString();
+    }
+
     var quotedValues = _.map(value, function(val) {
       return '\'' + val + '\'';
     });

public/app/plugins/datasource/postgres/module.ts

@@ -16,8 +16,8 @@ class PostgresConfigCtrl {
 
 const defaultQuery = `SELECT
   extract(epoch from time_column) AS time,
-  title_column as title,
-  description_column as text
+  text_column as text,
+  tags_column as tags
 FROM
   metric_table
 WHERE