diff --git a/src/Functions/if.cpp b/src/Functions/if.cpp
index ecee5590b35..6e46a03c69a 100644
--- a/src/Functions/if.cpp
+++ b/src/Functions/if.cpp
@@ -487,7 +487,7 @@ private:
                 conditional(ConstSource<StringSource>(*col_then_const), ConstSource<FixedStringSource>(*col_else_const_fixed), sink, cond_data);
             else if (col_then_const_fixed && col_else_const)
                 conditional(ConstSource<FixedStringSource>(*col_then_const_fixed), ConstSource<StringSource>(*col_else_const), sink, cond_data);
-            if (col_then_fixed && col_else_fixed)
+            else if (col_then_fixed && col_else_fixed)
                 conditional(FixedStringSource(*col_then_fixed), FixedStringSource(*col_else_fixed), sink, cond_data);
             else if (col_then_fixed && col_else_const_fixed)
                 conditional(FixedStringSource(*col_then_fixed), ConstSource<FixedStringSource>(*col_else_const_fixed), sink, cond_data);