diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index b5a9c8be56e..a12b804e6dc 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -11812,7 +11812,7 @@ get_func_sql_syntax(FuncExpr *expr, deparse_context *context)
 				Assert(IsA(con, Const) &&
 					   con->consttype == TEXTOID &&
 					   !con->constisnull);
-				appendStringInfoString(buf, TextDatumGetCString(con->constvalue));
+				appendStringInfoString(buf, quote_identifier(TextDatumGetCString(con->constvalue)));
 			}
 			appendStringInfoString(buf, " FROM ");
 			get_rule_expr((Node *) lsecond(expr->args), context, false);
@@ -11832,6 +11832,7 @@ get_func_sql_syntax(FuncExpr *expr, deparse_context *context)
 				Assert(IsA(con, Const) &&
 					   con->consttype == TEXTOID &&
 					   !con->constisnull);
+				/* NB: safe because no allowed words need quoted/escaped */
 				appendStringInfo(buf, " %s",
 								 TextDatumGetCString(con->constvalue));
 			}