diff --git a/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp b/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
index 8f7196183ce..a07f6f9995a 100644
--- a/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
+++ b/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
@@ -338,7 +338,7 @@ BlockInputStreams MergeTreeDataSelectExecutor::readFromParts(
         if (relative_sample_size == RelativeSize(1))
             relative_sample_size = 0;
 
-        if (relative_sample_offset > 0 && 0 == relative_sample_size)
+        if (relative_sample_offset > 0 && RelativeSize(0) == relative_sample_size)
             throw Exception("Sampling offset is incorrect because no sampling", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
 
         if (relative_sample_offset > 1)
@@ -389,7 +389,7 @@ BlockInputStreams MergeTreeDataSelectExecutor::readFromParts(
         if (!data.sampling_expression)
             throw Exception("Illegal SAMPLE: table doesn't support sampling", ErrorCodes::SAMPLING_NOT_SUPPORTED);
 
-        if (sample_factor_column_queried && relative_sample_size != 0)
+        if (sample_factor_column_queried && relative_sample_size != RelativeSize(0))
             used_sample_factor = 1.0 / boost::rational_cast<Float64>(relative_sample_size);
 
         RelativeSize size_of_universum = 0;