diff --git a/expr.cc b/expr.cc
index 99640bf..5f62e92 100644
--- a/expr.cc
+++ b/expr.cc
@@ -17,9 +17,8 @@ using impedance::matched;
 shared_ptr<value_expr> value_expr::factory(prod *p, sqltype *type_constraint, bool can_return_set)
 {
   try {
-    // ERROR:  aggregate window functions not yet supported
-    //if (1 == d20() && p->level < d6() && window_function::allowed(p))
-    //  return make_shared<window_function>(p, type_constraint);
+    if (1 == d20() && p->level < d6() && window_function::allowed(p))
+      return make_shared<window_function>(p, type_constraint);
     if (1 == d42() && p->level < d6() && type_constraint && type_constraint->name.rfind("list", 0) != 0 && type_constraint->name.rfind("map", 0) != 0 && type_constraint->name.rfind("record", 0) != 0 && type_constraint->name.rfind("any", 0) != 0)
       return make_shared<coalesce>(p, type_constraint);
     else if (1 == d42() && p->level < d6() && type_constraint && type_constraint->name.rfind("list", 0) != 0 && type_constraint->name.rfind("map", 0) != 0 && type_constraint->name.rfind("record", 0) != 0 && type_constraint->name.rfind("any", 0) != 0)
@@ -557,7 +556,7 @@ window_function::window_function(prod *p, sqltype *type_constraint)
   : value_expr(p)
 {
   match();
-  aggregate = make_shared<funcall>(this, type_constraint, true);
+  aggregate = make_shared<funcall>(this, type_constraint, true, true);
   type = aggregate->type;
   partition_by.push_back(make_shared<column_reference>(this));
   while(d6() > 4)
diff --git a/grammar.cc b/grammar.cc
index 542e829..8547fb0 100644
--- a/grammar.cc
+++ b/grammar.cc
@@ -800,7 +800,7 @@ void explain_stmt::out(std::ostream &out) {
   if (for_supported) {
     out << "for ";
   }
-  if(with_supported && d6() > 3) {
+  if(with_supported && d6() == 1) {
     out << "create materialized view mv as ";
   }
   out << *q;
diff --git a/postgres.cc b/postgres.cc
index ad20851..9b92c3c 100644
--- a/postgres.cc
+++ b/postgres.cc
@@ -344,8 +344,9 @@ schema_pqxx::schema_pqxx(std::string &conninfo, bool no_catalog) : c(conninfo)
     "ON mz_functions.return_type_id = ret_type.id "
     "WHERE mz_functions.name not in ('pg_event_trigger_table_rewrite_reason', 'percentile_cont', 'dense_rank', 'cume_dist', 'rank', 'test_rank', 'percent_rank', 'percentile_disc', 'mode', 'test_percentile_disc') "
     "AND mz_functions.name !~ '^ri_fkey_' "
-    "AND NOT (mz_functions.name in ('sum', 'avg') AND ret_type.oid = 1186) " // https://github.com/MaterializeInc/materialize/issues/18043
+    "AND NOT (mz_functions.name in ('sum', 'avg', 'avg_internal_v1') AND ret_type.oid = 1186) " // https://github.com/MaterializeInc/materialize/issues/18043
     "AND mz_functions.name <> 'array_agg' " // https://github.com/MaterializeInc/materialize/issues/18044
+    "AND (mz_functions.name <> 'string_agg' AND ret_type.oid = 17) " // string_agg on BYTEA not yet supported
     "AND NOT mz_functions.name in ('mz_all', 'mz_any') " // https://github.com/MaterializeInc/materialize/issues/18057
     "AND " + procedure_is_aggregate + " AND NOT " + procedure_is_window);
   for (auto row : r) {