count with fill(none) will drop 0 valued intervals

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### Features
 
 ### Bugfixes
+- [#5042](https://github.com/influxdb/influxdb/issues/5042): Count with fill(none) will drop 0 valued intervals.
 - [#5016](https://github.com/influxdb/influxdb/pull/5016): Don't panic if Meta data directory not writable. Thanks @oiooj
 - [#5059](https://github.com/influxdb/influxdb/pull/5059): Fix unmarshal of database error by client code. Thanks @farshidtz
 - [#4940](https://github.com/influxdb/influxdb/pull/4940): Fix distributed aggregate query query error. Thanks @li-ang

cmd/influxd/run/server_test.go

@@ -4377,6 +4377,24 @@ func TestServer_Query_Fill(t *testing.T) {
 			exp:     `{"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]]}]}]}`,
 			params:  url.Values{"db": []string{"db0"}},
 		},
+		&Query{
+			name:    "fill defaults to 0 for count",
+			command: `select count(val) from fills where time >= '2009-11-10T23:00:00Z' and time < '2009-11-10T23:00:20Z' group by time(5s)`,
+			exp:     `{"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",0],["2009-11-10T23:00:15Z",1]]}]}]}`,
+			params:  url.Values{"db": []string{"db0"}},
+		},
+		&Query{
+			name:    "fill none drops 0s for count",
+			command: `select count(val) from fills where time >= '2009-11-10T23:00:00Z' and time < '2009-11-10T23:00:20Z' group by time(5s) fill(none)`,
+			exp:     `{"results":[{"series":[{"name":"fills","columns":["time","count"],"values":[["2009-11-10T23:00:00Z",2],["2009-11-10T23:00:05Z",1],["2009-11-10T23:00:15Z",1]]}]}]}`,
+			params:  url.Values{"db": []string{"db0"}},
+		},
+		&Query{
+			name:    "fill previous overwrites 0s for count",
+			command: `select count(val) from fills where time >= '2009-11-10T23:00:00Z' and time < '2009-11-10T23:00:20Z' group by time(5s) fill(previous)`,
+			exp:     `{"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",1],["2009-11-10T23:00:15Z",1]]}]}]}`,
+			params:  url.Values{"db": []string{"db0"}},
+		},
 	}...)
 
 	for i, query := range test.queries {

tsdb/aggregate.go

@@ -322,6 +322,7 @@ func (e *AggregateExecutor) processFill(results [][]interface{}) [][]interface{}
 		return results
 	}
 
+	isCount := e.stmt.HasSimpleCount()
 	if e.stmt.Fill == influxql.NoFill {
 		// remove any rows that have even one nil value. This one is tricky because they could have multiple
 		// aggregates, but this option means that any row that has even one nil gets purged.
@@ -330,7 +331,7 @@ func (e *AggregateExecutor) processFill(results [][]interface{}) [][]interface{}
 			hasNil := false
 			// start at 1 because the first value is always time
 			for j := 1; j < len(vals); j++ {
-				if vals[j] == nil {
+				if vals[j] == nil || (isCount && isZero(vals[j])) {
 					hasNil = true
 					break
 				}
@@ -342,7 +343,6 @@ func (e *AggregateExecutor) processFill(results [][]interface{}) [][]interface{}
 		return newResults
 	}
 
-	isCount := e.stmt.HasSimpleCount()
 	// They're either filling with previous values or a specific number
 	for i, vals := range results {
 		// start at 1 because the first value is always time