diff --git a/src/Parsers/ASTFunction.cpp b/src/Parsers/ASTFunction.cpp
index 0197421275c..4fec590a3b8 100644
--- a/src/Parsers/ASTFunction.cpp
+++ b/src/Parsers/ASTFunction.cpp
@@ -217,13 +217,13 @@ void ASTFunction::formatImplWithoutAlias(const FormatSettings & settings, Format
             const char * operators[] =
             {
                 "negate", "-",
-                "not", "NOT",
+                "not", "NOT ",
                 nullptr
             };
 
             for (const char ** func = operators; *func; func += 2)
             {
-                if (strcmp(name.c_str(), func[0]) != 0)
+                if (strcasecmp(name.c_str(), func[0]) != 0)
                 {
                     continue;
                 }