diff --git a/dbms/src/AggregateFunctions/AggregateFunctionMaxIntersections.h b/dbms/src/AggregateFunctions/AggregateFunctionMaxIntersections.h
index ebc283c03fc..11ec01e52e4 100644
--- a/dbms/src/AggregateFunctions/AggregateFunctionMaxIntersections.h
+++ b/dbms/src/AggregateFunctions/AggregateFunctionMaxIntersections.h
@@ -9,6 +9,7 @@
 #include <IO/WriteHelpers.h>
 
 #include <Common/ArenaAllocator.h>
+#include <Common/NaNUtils.h>
 
 #include <AggregateFunctions/IAggregateFunction.h>
 
@@ -90,8 +91,11 @@ public:
         PointType left = static_cast<const ColumnVector<PointType> &>(*columns[0]).getData()[row_num];
         PointType right = static_cast<const ColumnVector<PointType> &>(*columns[1]).getData()[row_num];
 
-        this->data(place).value.push_back(std::make_pair(left, Int64(1)), arena);
-        this->data(place).value.push_back(std::make_pair(right, Int64(-1)), arena);
+        if (!isNaN(left))
+            this->data(place).value.push_back(std::make_pair(left, Int64(1)), arena);
+
+        if (!isNaN(right))
+            this->data(place).value.push_back(std::make_pair(right, Int64(-1)), arena);
     }
 
     void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena * arena) const override
@@ -133,7 +137,6 @@ public:
         /// const_cast because we will sort the array
         auto & array = const_cast<typename MaxIntersectionsData<PointType>::Array &>(this->data(place).value);
 
-        /// TODO NaNs?
         std::sort(array.begin(), array.end(), [](const auto & a, const auto & b) { return a.first < b.first; });
 
         for (const auto & point_weight : array)
diff --git a/dbms/src/AggregateFunctions/QuantileExact.h b/dbms/src/AggregateFunctions/QuantileExact.h
index c134ad1653d..568ad8d0950 100644
--- a/dbms/src/AggregateFunctions/QuantileExact.h
+++ b/dbms/src/AggregateFunctions/QuantileExact.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Common/PODArray.h>
+#include <Common/NaNUtils.h>
 #include <IO/WriteBuffer.h>
 #include <IO/ReadBuffer.h>
 #include <Core/Types.h>
@@ -32,7 +33,9 @@ struct QuantileExact
 
     void add(const Value & x)
     {
-        array.push_back(x);
+        /// We must skip NaNs as they are not compatible with comparison sorting.
+        if (!isNaN(x))
+            array.push_back(x);
     }
 
     template <typename Weight>
diff --git a/dbms/src/AggregateFunctions/QuantileExactWeighted.h b/dbms/src/AggregateFunctions/QuantileExactWeighted.h
index f524426392a..76e65f07dac 100644
--- a/dbms/src/AggregateFunctions/QuantileExactWeighted.h
+++ b/dbms/src/AggregateFunctions/QuantileExactWeighted.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Common/HashTable/HashMap.h>
+#include <Common/NaNUtils.h>
 
 
 namespace DB
@@ -33,12 +34,15 @@ struct QuantileExactWeighted
 
     void add(const Value & x)
     {
-        ++map[x];
+        /// We must skip NaNs as they are not compatible with comparison sorting.
+        if (!isNaN(x))
+            ++map[x];
     }
 
     void add(const Value & x, const Weight & weight)
     {
-        map[x] += weight;
+        if (!isNaN(x))
+            map[x] += weight;
     }
 
     void merge(const QuantileExactWeighted & rhs)
diff --git a/dbms/src/AggregateFunctions/QuantilesCommon.h b/dbms/src/AggregateFunctions/QuantilesCommon.h
index 53802834379..1f70fde74dd 100644
--- a/dbms/src/AggregateFunctions/QuantilesCommon.h
+++ b/dbms/src/AggregateFunctions/QuantilesCommon.h
@@ -4,6 +4,7 @@
 
 #include <Core/Field.h>
 #include <Common/FieldVisitors.h>
+#include <Common/NaNUtils.h>
 
 
 namespace DB
@@ -12,6 +13,7 @@ namespace DB
 namespace ErrorCodes
 {
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
+    extern const int PARAMETER_OUT_OF_BOUND;
 }
 
 
@@ -55,6 +57,10 @@ struct QuantileLevels
         for (size_t i = 0; i < size; ++i)
         {
             levels[i] = applyVisitor(FieldVisitorConvertToNumber<Float64>(), params[i]);
+
+            if (isNaN(levels[i]) || levels[i] < 0 || levels[i] > 1)
+                throw Exception("Quantile level is out of range [0..1]", ErrorCodes::PARAMETER_OUT_OF_BOUND);
+
             permutation[i] = i;
         }
 
diff --git a/dbms/src/AggregateFunctions/ReservoirSampler.h b/dbms/src/AggregateFunctions/ReservoirSampler.h
index 77d9f7285b7..ad5bf10f48f 100644
--- a/dbms/src/AggregateFunctions/ReservoirSampler.h
+++ b/dbms/src/AggregateFunctions/ReservoirSampler.h
@@ -9,6 +9,7 @@
 #include <IO/ReadHelpers.h>
 #include <IO/WriteHelpers.h>
 #include <Common/PODArray.h>
+#include <Common/NaNUtils.h>
 #include <Poco/Exception.h>
 #include <pcg_random.hpp>
 
@@ -67,6 +68,9 @@ public:
 
     void insert(const T & v)
     {
+        if (isNaN(v))
+            return;
+
         sorted = false;
         ++total_values;
         if (samples.size() < sample_count)
diff --git a/dbms/src/AggregateFunctions/ReservoirSamplerDeterministic.h b/dbms/src/AggregateFunctions/ReservoirSamplerDeterministic.h
index bff3fcb78ea..44760d8e5a5 100644
--- a/dbms/src/AggregateFunctions/ReservoirSamplerDeterministic.h
+++ b/dbms/src/AggregateFunctions/ReservoirSamplerDeterministic.h
@@ -11,6 +11,7 @@
 #include <IO/ReadHelpers.h>
 #include <IO/WriteHelpers.h>
 #include <Common/PODArray.h>
+#include <Common/NaNUtils.h>
 #include <Poco/Exception.h>
 
 
@@ -66,6 +67,9 @@ public:
 
     void insert(const T & v, const UInt64 determinator)
     {
+        if (isNaN(v))
+            return;
+
         const UInt32 hash = intHash64(determinator);
         if (!good(hash))
             return;
diff --git a/dbms/tests/queries/0_stateless/00606_quantiles_and_nans.reference b/dbms/tests/queries/0_stateless/00606_quantiles_and_nans.reference
new file mode 100644
index 00000000000..d00491fd7e5
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00606_quantiles_and_nans.reference
@@ -0,0 +1 @@
+1
diff --git a/dbms/tests/queries/0_stateless/00606_quantiles_and_nans.sql b/dbms/tests/queries/0_stateless/00606_quantiles_and_nans.sql
new file mode 100644
index 00000000000..c89883e356b
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00606_quantiles_and_nans.sql
@@ -0,0 +1 @@
+SELECT DISTINCT eq FROM (WITH range(number % 10) AS arr, arrayMap(x -> x = intDiv(number, 10) ? nan : x, arr) AS arr_with_nan, arrayFilter(x -> x != intDiv(number, 10), arr) AS arr_filtered SELECT number, arrayReduce('quantileExact', arr_with_nan) AS q1, arrayReduce('quantileExact', arr_filtered) AS q2, q1 = q2 AS eq FROM numbers(100));
\ No newline at end of file