diff --git a/src/common/backend/parser/gram.y b/src/common/backend/parser/gram.y
index 03947af9c..6a60f6efc 100644
--- a/src/common/backend/parser/gram.y
+++ b/src/common/backend/parser/gram.y
@@ -25802,5 +25802,6 @@ static void RemoveFillerCol(List *filler_list, List *col_list)
 #undef yyerror
 #undef yylval
 #undef yylloc
+#undef yylex
 
 #include "scan.inc"
diff --git a/src/gausskernel/storage/replication/repl_gram.y b/src/gausskernel/storage/replication/repl_gram.y
index b38cc7e15..1c65c3cff 100755
--- a/src/gausskernel/storage/replication/repl_gram.y
+++ b/src/gausskernel/storage/replication/repl_gram.y
@@ -445,4 +445,6 @@ replication_yylex(YYSTYPE *lvalp, YYLTYPE *llocp,
 	return replication_scanner_yylex(&(lvalp->yy_core), llocp, yyscanner);
 }
 
+#undef yylex
+
 #include "repl_scanner.inc"
diff --git a/src/gausskernel/storage/replication/syncrep_gram.y b/src/gausskernel/storage/replication/syncrep_gram.y
index e435f4ef2..9f082cafa 100644
--- a/src/gausskernel/storage/replication/syncrep_gram.y
+++ b/src/gausskernel/storage/replication/syncrep_gram.y
@@ -170,5 +170,6 @@ create_syncrep_config(const char *num_sync, List *members, uint8 syncrep_method)
 #undef yyerror
 #undef yylval
 #undef yylloc
+#undef yylex
 
 #include "syncrep_scanner.inc"