diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 299e887..a1165fa 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -2881,15 +2881,15 @@ getBlobs(Archive *fout)
 						  username_subquery);
 	else if (fout->remoteVersion >= 70100)
 		appendPQExpBufferStr(blobQry,
-							 "SELECT DISTINCT loid, NULL::oid, NULL, "
-							 "NULL AS rlomacl, NULL AS initlomacl, "
-							 "NULL AS initrlomacl "
+							 "SELECT DISTINCT loid, NULL::oid, NULL::oid, "
+							 "NULL::oid AS rlomacl, NULL::oid AS initlomacl, "
+							 "NULL::oid AS initrlomacl "
 							 " FROM pg_largeobject");
 	else
 		appendPQExpBufferStr(blobQry,
-							 "SELECT oid, NULL::oid, NULL, "
-							 "NULL AS rlomacl, NULL AS initlomacl, "
-							 "NULL AS initrlomacl "
+							 "SELECT oid, NULL::oid, NULL::oid, "
+							 "NULL::oid AS rlomacl, NULL::oid AS initlomacl, "
+							 "NULL::oid AS initrlomacl "
 							 " FROM pg_class WHERE relkind = 'l'");
 
 	res = ExecuteSqlQuery(fout, blobQry->data, PGRES_TUPLES_OK);