Merge pull request #2295 from influxdb/check_null_fix

Use nil as default return value for MapCount

CHANGELOG.md

@@ -12,6 +12,7 @@
 - [#2276](https://github.com/influxdb/influxdb/pull/2276): Broker topic truncation.
 - [#2292](https://github.com/influxdb/influxdb/pull/2292): Wire up drop CQ statement - thanks @neonstalwart!
 - [#2290](https://github.com/influxdb/influxdb/pull/2290): Allow hostname argument to override default config - thanks @neonstalwart!
+- [#2295](https://github.com/influxdb/influxdb/pull/2295): Use nil as default return value for MapCount - thanks @neonstalwart!
 
 ## v0.9.0-rc24 [2015-04-13]
 

cmd/influxd/server_integration_test.go

@@ -912,6 +912,16 @@ func runTestsData(t *testing.T, testName string, nodes Cluster, database, retent
 			query:    `select mean(val) from "%DB%"."%RP%".fills where time >= '2009-11-10T23:00:00Z' and time < '2009-11-10T23:00:20Z' group by time(5s)`,
 			expected: `{"results":[{"series":[{"name":"fills","columns":["time","mean"],"values":[["2009-11-10T23:00:00Z",4],["2009-11-10T23:00:05Z",4],["2009-11-10T23:00:10Z",null],["2009-11-10T23:00:15Z",10]]}]}]}`,
 		},
+		{
+			name:     "fill with count aggregate defaults to null",
+			query:    `select count(val) from "%DB%"."%RP%".fills where time >= '2009-11-10T23:00:00Z' and time < '2009-11-10T23:00:20Z' group by time(5s)`,
+			expected: `{"results":[{"series":[{"name":"fills","columns":["time","count"],"values":[["2009-11-10T23:00:00Z",2],["2009-11-10T23:00:05Z",1],["2009-11-10T23:00:10Z",null],["2009-11-10T23:00:15Z",1]]}]}]}`,
+		},
+		{
+			name:     "fill with count aggregate specific value",
+			query:    `select count(val) from "%DB%"."%RP%".fills where time >= '2009-11-10T23:00:00Z' and time < '2009-11-10T23:00:20Z' group by time(5s) fill(1234)`,
+			expected: `{"results":[{"series":[{"name":"fills","columns":["time","count"],"values":[["2009-11-10T23:00:00Z",2],["2009-11-10T23:00:05Z",1],["2009-11-10T23:00:10Z",1234],["2009-11-10T23:00:15Z",1]]}]}]}`,
+		},
 
 		// Drop Measurement, series tags preserved tests
 		{

influxql/functions.go

@@ -165,11 +165,14 @@ func InitializeUnmarshaller(c *Call) (UnmarshalFunc, error) {
 
 // MapCount computes the number of values in an iterator.
 func MapCount(itr Iterator) interface{} {
-	n := 0
+	n := float64(0)
 	for _, k, _ := itr.Next(); k != 0; _, k, _ = itr.Next() {
 		n++
 	}
-	return float64(n)
+	if n > 0 {
+		return n
+	}
+	return nil
 }
 
 // MapSum computes the summation of values in an iterator.