diff --git a/dbms/src/DataTypes/FieldToDataType.cpp b/dbms/src/DataTypes/FieldToDataType.cpp
index 3086c9167c2..18fa0e97b88 100644
--- a/dbms/src/DataTypes/FieldToDataType.cpp
+++ b/dbms/src/DataTypes/FieldToDataType.cpp
@@ -8,7 +8,6 @@
 #include <DataTypes/DataTypeNullable.h>
 #include <DataTypes/DataTypeNothing.h>
 #include <DataTypes/getLeastSupertype.h>
-#include <Interpreters/convertFieldToType.h>
 #include <Common/Exception.h>
 #include <ext/size.h>
 
diff --git a/dbms/src/Functions/FunctionsRound.h b/dbms/src/Functions/FunctionsRound.h
index 92d70633c12..3c9be5f15b9 100644
--- a/dbms/src/Functions/FunctionsRound.h
+++ b/dbms/src/Functions/FunctionsRound.h
@@ -7,7 +7,6 @@
 #include <DataTypes/getLeastSupertype.h>
 #include <DataTypes/DataTypeArray.h>
 #include <Interpreters/castColumn.h>
-#include <Interpreters/convertFieldToType.h>
 
 #include <common/intExp.h>
 #include <cmath>
@@ -608,33 +607,28 @@ public:
 
     void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t) override
     {
-        const ColumnConst * array = checkAndGetColumnConst<ColumnArray>(block.getByPosition(arguments[1]).column.get());
-        if (!array)
-        {
-            throw Exception{"Second argument of function " + getName() + " must be constant array.", ErrorCodes::ILLEGAL_COLUMN};
-        }
-
         auto in_column = block.getByPosition(arguments[0]).column;
         const auto & in_type = block.getByPosition(arguments[0]).type;
 
+        auto array_column = block.getByPosition(arguments[1]).column;
+        const auto & array_type = block.getByPosition(arguments[1]).type;
+
         const auto & return_type = block.getByPosition(result).type;
         auto column_result = return_type->createColumn();
         auto out = column_result.get();
 
         if (!in_type->equals(*return_type))
-        {
             in_column = castColumn(block.getByPosition(arguments[0]), return_type, context);
-        }
+
+        if (!array_type->equals(*return_type))
+            array_column = castColumn(block.getByPosition(arguments[1]), std::make_shared<DataTypeArray>(return_type), context);
 
         const auto in = in_column.get();
-        auto boundaries = array->getValue<Array>();
+        auto boundaries = typeid_cast<const ColumnConst &>(*array_column).getValue<Array>();
         size_t num_boundaries = boundaries.size();
         if (!num_boundaries)
             throw Exception("Empty array is illegal for boundaries in " + getName() + " function", ErrorCodes::BAD_ARGUMENTS);
 
-        for (size_t i = 0; i < num_boundaries; ++i)
-            boundaries[i] = convertFieldToType(boundaries[i], *return_type);
-
         if (!executeNum<UInt8>(in, out, boundaries)
             && !executeNum<UInt16>(in, out, boundaries)
             && !executeNum<UInt32>(in, out, boundaries)
diff --git a/dbms/tests/queries/0_stateless/00805_round_down.reference b/dbms/tests/queries/0_stateless/00805_round_down.reference
index b37e8c8f1a0..0ed04c7757f 100644
--- a/dbms/tests/queries/0_stateless/00805_round_down.reference
+++ b/dbms/tests/queries/0_stateless/00805_round_down.reference
@@ -61,3 +61,23 @@
 0.07000	4.00000
 0.08000	4.00000
 0.09000	4.00000
+0.00000	0.04000
+0.01000	0.04000
+0.02000	0.04000
+0.03000	0.04000
+0.04000	0.04000
+0.05000	0.05000
+0.06000	0.06000
+0.07000	0.06000
+0.08000	0.06000
+0.09000	0.06000
+0.00000	0.04000
+0.01000	0.04000
+0.02000	0.04000
+0.03000	0.04000
+0.04000	0.04000
+0.05000	0.05000
+0.06000	0.06000
+0.07000	0.06000
+0.08000	0.06000
+0.09000	0.06000
diff --git a/dbms/tests/queries/0_stateless/00805_round_down.sql b/dbms/tests/queries/0_stateless/00805_round_down.sql
index 0ba4804031c..bf25f7be952 100644
--- a/dbms/tests/queries/0_stateless/00805_round_down.sql
+++ b/dbms/tests/queries/0_stateless/00805_round_down.sql
@@ -7,6 +7,7 @@ SELECT 1 as x, roundDown(x, [6, 5, 4]);
 SET send_logs_level = 'none';
 SELECT 1 as x, roundDown(x, []); -- { serverError 43 }
 SELECT 1 as x, roundDown(x, emptyArrayUInt8()); -- { serverError 44 }
+SELECT roundDown(number, [number]) FROM system.numbers LIMIT 10; -- { serverError 44 }
 
 SELECT 1 as x, roundDown(x, [1]);
 SELECT 1 as x, roundDown(x, [1.5]);
@@ -14,4 +15,5 @@ SELECT 1 as x, roundDown(x, [1.5]);
 SELECT number % 10 as x, roundDown(x, (SELECT groupArray(number * 1.25) FROM numbers(100000))) FROM system.numbers LIMIT 10;
 
 SELECT toDecimal64(number, 5) / 100 as x, roundDown(x, [4, 5, 6]) FROM system.numbers LIMIT 10;
-
+SELECT toDecimal64(number, 5) / 100 as x, roundDown(x, [toDecimal64(0.04, 5), toDecimal64(0.05, 5), toDecimal64(0.06, 5)]) FROM system.numbers LIMIT 10;
+SELECT toDecimal64(number, 5) / 100 as x, roundDown(x, [toDecimal32(0.04, 2), toDecimal32(0.05, 2), toDecimal32(0.06, 2)]) FROM system.numbers LIMIT 10;