From 1e4cc12bd07638550fc4dceb064526fe2288b29a Mon Sep 17 00:00:00 2001
From: Matt Jaffee <matthew.jaffee@gmail.com>
Date: Tue, 2 Mar 2021 21:47:27 -0600
Subject: [PATCH] handle 0th percentile properly

---
 executor.go      | 4 ++++
 executor_test.go | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/executor.go b/executor.go
index a0e92ea4b..5025c01a2 100644
--- a/executor.go
+++ b/executor.go
@@ -1361,6 +1361,10 @@ func (e *executor) executePercentile(ctx context.Context, qcx *Qcx, index string
 		rangeCall = intersectCall.Children[0]
 	}
 
+	if nth == 0.0 {
+		return ValCount{Val: minVal.Val, Count: minVal.Count}, nil
+	}
+
 	k := (1 - nth) / nth
 
 	min, max := minVal.Val, maxVal.Val
diff --git a/executor_test.go b/executor_test.go
index 7712c4095..63b015816 100644
--- a/executor_test.go
+++ b/executor_test.go
@@ -6916,6 +6916,9 @@ func variousQueriesOnPercentiles(t *testing.T, c *test.Cluster) {
 				max = num
 			}
 		}
+		if nth == 0.0 {
+			return min
+		}
 		k := (1 - nth) / nth
 
 		possibleNthVal := int64(0)
@@ -6990,7 +6993,7 @@ func variousQueriesOnPercentiles(t *testing.T, c *test.Cluster) {
 	}
 
 	// generate test cases per each nth argument
-	nths := []float64{0.1, 0.25, 0.5, 0.75, 0.9, 0.99}
+	nths := []float64{0.0, 0.1, 0.25, 0.5, 0.75, 0.9, 0.99}
 	var tests []testCase
 	for _, nth := range nths {
 		query := fmt.Sprintf(`Percentile(field="net_worth", filter=Row(val="foo"), nth=%f)`, nth)