diff --git a/src/Parsers/ASTSelectQuery.cpp b/src/Parsers/ASTSelectQuery.cpp
index 3be3f6c5c9a..7537628b3a5 100644
--- a/src/Parsers/ASTSelectQuery.cpp
+++ b/src/Parsers/ASTSelectQuery.cpp
@@ -491,7 +491,7 @@ bool ASTSelectQuery::hasQueryParameters() const
         if (ast->as<ASTQueryParameter>())
             return true;
 
-        for (auto child : ast->children)
+        for (const auto & child : ast->children)
             queue.push(child);
     }
     return false;
diff --git a/src/Parsers/ASTSelectWithUnionQuery.cpp b/src/Parsers/ASTSelectWithUnionQuery.cpp
index c38e4e2c747..76fe9582615 100644
--- a/src/Parsers/ASTSelectWithUnionQuery.cpp
+++ b/src/Parsers/ASTSelectWithUnionQuery.cpp
@@ -104,7 +104,7 @@ bool ASTSelectWithUnionQuery::hasQueryParameters() const
                 return true;
         }
 
-        for (auto child : current->children)
+        for (const auto & child : current->children)
             queue.push(child);
     }
     return false;