address comment

Signed-off-by: jyz0309 <45495947@qq.com>

docs/querying/operators.md

@@ -241,7 +241,7 @@ vector. `by` and `without` are only used to bucket the input vector.
 `quantile` calculates the φ-quantile, the value that ranks at number φ*N among
 the N metric values of the dimensions aggregated over. φ is provided as the
 aggregation parameter. For example, `quantile(0.5, ...)` calculates the median,
-`quantile(0.95, ...)` the 95th percentile. For φ = `NaN`, `NaN` is returned. 
+`quantile(0.95, ...)` the 95th percentile. For φ = `NaN`, `NaN` is returned. For φ < 0, `-Inf` is returned. For φ > 1, `+Inf` is returned.
 
 Example:
 

promql/quantile.go

@@ -186,7 +186,7 @@ func ensureMonotonic(buckets buckets) {
 // quantile calculates the given quantile of a vector of samples.
 //
 // The Vector will be sorted.
-// If 'values' has zero elements
+// If 'values' has zero elements, NaN is returned.
 // If q==NaN, NaN is returned.
 // If q<0, -Inf is returned.
 // If q>1, +Inf is returned.

promql/testdata/aggregators.test

@@ -399,6 +399,11 @@ eval instant at 1m quantile without(point)((scalar(foo)), data)
 	{test="three samples"} 1.6
 	{test="uneven samples"} 2.8
 
+eval instant at 1m quantile without(point)(NaN, data)
+    {test="two samples"} NaN
+    {test="three samples"} NaN
+    {test="uneven samples"} NaN
+
 # Tests for group.
 clear