If no points to count, count is 0

Fix issue #4701.
influxdata · Nov 13, 2015 · f889ac1 · f889ac1
1 parent 76eca03
commit f889ac1
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/cmd/influxd/run/server_test.go b/cmd/influxd/run/server_test.go
@@ -1146,6 +1146,11 @@ func TestServer_Query_Count(t *testing.T) {
 			command: fmt.Sprintf(`SELECT count(value) FROM db0.rp0.cpu WHERE time >= '%s'`, hour_ago.Format(time.RFC3339Nano)),
 			exp:     fmt.Sprintf(`{"results":[{"series":[{"name":"cpu","columns":["time","count"],"values":[["%s",1]]}]}]}`, hour_ago.Format(time.RFC3339Nano)),
 		},
+		&Query{
+			name:    "selecting count(value) with filter that excludes all results should return 0",
+			command: fmt.Sprintf(`SELECT count(value) FROM db0.rp0.cpu WHERE value=100 AND time >= '%s'`, hour_ago.Format(time.RFC3339Nano)),
+			exp:     fmt.Sprintf(`{"results":[{"series":[{"name":"cpu","columns":["time","count"],"values":[["%s",0]]}]}]}`, hour_ago.Format(time.RFC3339Nano)),
+		},
 		&Query{
 			name:    "selecting count(*) should error",
 			command: `SELECT count(*) FROM db0.rp0.cpu`,

diff --git a/tsdb/functions.go b/tsdb/functions.go
@@ -250,10 +250,7 @@ func MapCount(input *MapInput) interface{} {
 	for range input.Items {
 		n++
 	}
-	if n > 0 {
-		return n
-	}
-	return nil
+	return n
 }
 
 type InterfaceValues []interface{}