diff --git a/src/bin/scripts/vacuumdb.c b/src/bin/scripts/vacuumdb.c
index 249622068a..d07ab7d67e 100644
--- a/src/bin/scripts/vacuumdb.c
+++ b/src/bin/scripts/vacuumdb.c
@@ -684,7 +684,8 @@ vacuum_one_database(ConnParams *cparams,
 	 * Exclude temporary tables, beginning the WHERE clause.
 	 */
 	appendPQExpBufferStr(&catalog_query,
-						 " WHERE c.relpersistence != " CppAsString2(RELPERSISTENCE_TEMP));
+						 " WHERE c.relpersistence OPERATOR(pg_catalog.!=) "
+						 CppAsString2(RELPERSISTENCE_TEMP) "\n");
 
 	/*
 	 * Used to match the tables or schemas listed by the user, for the WHERE