diff --git a/dbms/src/Interpreters/AnalyzedJoin.h b/dbms/src/Interpreters/AnalyzedJoin.h
index a2df2ff6bab..6c5c65cde54 100644
--- a/dbms/src/Interpreters/AnalyzedJoin.h
+++ b/dbms/src/Interpreters/AnalyzedJoin.h
@@ -90,7 +90,7 @@ public:
     const SizeLimits & sizeLimits() const { return size_limits; }
     VolumePtr getTemporaryVolume() { return tmp_volume; }
     bool allowMergeJoin() const;
-    bool preferMergeJoin() const { return allowMergeJoin() && join_algorithm == JoinAlgorithm::PREFER_PARTIAL_MERGE; }
+    bool preferMergeJoin() const { return join_algorithm == JoinAlgorithm::PREFER_PARTIAL_MERGE; }
     bool forceMergeJoin() const { return join_algorithm == JoinAlgorithm::PARTIAL_MERGE; }
     bool forceHashJoin() const { return join_algorithm == JoinAlgorithm::HASH; }
 
diff --git a/dbms/src/Interpreters/ExpressionAnalyzer.cpp b/dbms/src/Interpreters/ExpressionAnalyzer.cpp
index 59115d30422..1a727795edf 100644
--- a/dbms/src/Interpreters/ExpressionAnalyzer.cpp
+++ b/dbms/src/Interpreters/ExpressionAnalyzer.cpp
@@ -542,9 +542,11 @@ static ExpressionActionsPtr createJoinedBlockActions(const Context & context, co
 
 static std::shared_ptr<IJoin> makeJoin(std::shared_ptr<AnalyzedJoin> analyzed_join, const Block & sample_block)
 {
-    if (analyzed_join->forceHashJoin())
+    bool allow_merge_join = analyzed_join->allowMergeJoin();
+
+    if (analyzed_join->forceHashJoin() || (analyzed_join->preferMergeJoin() && !allow_merge_join))
         return std::make_shared<Join>(analyzed_join, sample_block);
-    else if (analyzed_join->forceMergeJoin() || analyzed_join->preferMergeJoin())
+    else if (analyzed_join->forceMergeJoin() || (analyzed_join->preferMergeJoin() && allow_merge_join))
         return std::make_shared<MergeJoin>(analyzed_join, sample_block);
     return std::make_shared<JoinSwitcher>(analyzed_join, sample_block);
 }