diff --git a/dbms/src/DataTypes/DataTypeDateTime64.cpp b/dbms/src/DataTypes/DataTypeDateTime64.cpp
index af92d446f55..fa2cd3d18ee 100644
--- a/dbms/src/DataTypes/DataTypeDateTime64.cpp
+++ b/dbms/src/DataTypes/DataTypeDateTime64.cpp
@@ -69,7 +69,7 @@ void DataTypeDateTime64::serializeText(const IColumn & column, size_t row_num, W
 
 void DataTypeDateTime64::deserializeText(IColumn & column, ReadBuffer & istr, const FormatSettings &) const
 {
-    DateTime64 result;
+    DateTime64 result = 0;
     readDateTime64Text(result, this->getScale(), istr, time_zone);
     assert_cast<ColumnType &>(column).getData().push_back(result);
 }
@@ -86,7 +86,7 @@ void DataTypeDateTime64::serializeTextEscaped(const IColumn & column, size_t row
 
 void DataTypeDateTime64::deserializeTextEscaped(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
 {
-    DateTime64 x;
+    DateTime64 x = 0;
     ::readText(x, scale, istr, settings, time_zone, utc_time_zone);
     assert_cast<ColumnType &>(column).getData().push_back(x);
 }
@@ -100,7 +100,7 @@ void DataTypeDateTime64::serializeTextQuoted(const IColumn & column, size_t row_
 
 void DataTypeDateTime64::deserializeTextQuoted(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
 {
-    DateTime64 x;
+    DateTime64 x = 0;
     if (checkChar('\'', istr)) /// Cases: '2017-08-31 18:36:48' or '1504193808'
     {
         ::readText(x, scale, istr, settings, time_zone, utc_time_zone);
@@ -122,7 +122,7 @@ void DataTypeDateTime64::serializeTextJSON(const IColumn & column, size_t row_nu
 
 void DataTypeDateTime64::deserializeTextJSON(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
 {
-    DateTime64 x;
+    DateTime64 x = 0;
     if (checkChar('"', istr))
     {
         ::readText(x, scale, istr, settings, time_zone, utc_time_zone);
@@ -144,7 +144,7 @@ void DataTypeDateTime64::serializeTextCSV(const IColumn & column, size_t row_num
 
 void DataTypeDateTime64::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const
 {
-    DateTime64 x;
+    DateTime64 x = 0;
 
     if (istr.eof())
         throwReadAfterEOF();
@@ -172,7 +172,7 @@ void DataTypeDateTime64::serializeProtobuf(const IColumn & column, size_t row_nu
 void DataTypeDateTime64::deserializeProtobuf(IColumn & column, ProtobufReader & protobuf, bool allow_add_row, bool & row_added) const
 {
     row_added = false;
-    DateTime64 t;
+    DateTime64 t = 0;
     if (!protobuf.readDateTime64(t, scale))
         return;
 
diff --git a/dbms/src/Functions/FunctionsConversion.h b/dbms/src/Functions/FunctionsConversion.h
index 60059b00762..5b5f385427d 100644
--- a/dbms/src/Functions/FunctionsConversion.h
+++ b/dbms/src/Functions/FunctionsConversion.h
@@ -641,7 +641,7 @@ struct ConvertThroughParsing
                 {
                     if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
                     {
-                        DateTime64 res;
+                        DateTime64 res = 0;
                         parseDateTime64BestEffort(res, vec_to.getScale(), read_buffer, *local_time_zone, *utc_time_zone);
                         vec_to[i] = res;
                     }
@@ -656,7 +656,7 @@ struct ConvertThroughParsing
                 {
                     if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
                     {
-                        DateTime64 value;
+                        DateTime64 value = 0;
                         readDateTime64Text(value, vec_to.getScale(), read_buffer, *local_time_zone);
                         vec_to[i] = value;
                     }
@@ -677,7 +677,7 @@ struct ConvertThroughParsing
                 {
                     if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
                     {
-                        DateTime64 res;
+                        DateTime64 res = 0;
                         parsed = tryParseDateTime64BestEffort(res, vec_to.getScale(), read_buffer, *local_time_zone, *utc_time_zone);
                         vec_to[i] = res;
                     }
@@ -692,7 +692,7 @@ struct ConvertThroughParsing
                 {
                     if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
                     {
-                        DateTime64 value;
+                        DateTime64 value = 0;
                         parsed = tryReadDateTime64Text(value, vec_to.getScale(), read_buffer, *local_time_zone);
                         vec_to[i] = value;
                     }
@@ -1132,7 +1132,7 @@ public:
             res = std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, 1, 0));
         else if constexpr (to_decimal)
         {
-            UInt64 scale = extractToDecimalScale(arguments[1]);
+            UInt64 scale [[maybe_unused]] = extractToDecimalScale(arguments[1]);
 
             if constexpr (std::is_same_v<ToDataType, DataTypeDecimal<Decimal32>>)
                 res = createDecimal<DataTypeDecimal>(9, scale);
diff --git a/dbms/src/IO/parseDateTimeBestEffort.cpp b/dbms/src/IO/parseDateTimeBestEffort.cpp
index e2eaecfc68c..29137cc63de 100644
--- a/dbms/src/IO/parseDateTimeBestEffort.cpp
+++ b/dbms/src/IO/parseDateTimeBestEffort.cpp
@@ -543,7 +543,7 @@ bool tryParseDateTimeBestEffort(time_t & res, ReadBuffer & in, const DateLUTImpl
 
 void parseDateTime64BestEffort(DateTime64 & res, UInt32 scale, ReadBuffer & in, const DateLUTImpl & local_time_zone, const DateLUTImpl & utc_time_zone)
 {
-    DateTime64::NativeType whole;
+    time_t whole;
     DateTime64::NativeType fractional;
     parseDateTimeBestEffortImpl<void>(whole, in, local_time_zone, utc_time_zone, &fractional);