diff --git a/mysql-test/main/join.result b/mysql-test/main/join.result
index b9543fc2c43..859bc588ed4 100644
--- a/mysql-test/main/join.result
+++ b/mysql-test/main/join.result
@@ -3407,3 +3407,20 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 drop table t1,t2,t3;
 drop table t1000,t10,t03;
 # End of 10.3 tests
+#
+# MDEV-30080 Wrong result with LEFT JOINs involving constant tables
+#
+CREATE TABLE t1 (a INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 (b INT) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1),(1);
+CREATE TABLE t3 (c INT PRIMARY KEY) ENGINE=MyISAM;
+SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b = t3.c) ON t1.a = t2.b;
+a	b	c
+1	1	NULL
+1	1	NULL
+SELECT COUNT(*) FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b = t3.c) ON t1.a = t2.b;
+COUNT(*)
+2
+DROP TABLE t1, t2, t3;
+# End of 10.5 tests
diff --git a/mysql-test/main/join.test b/mysql-test/main/join.test
index b99f05f7c88..c8bd2886b30 100644
--- a/mysql-test/main/join.test
+++ b/mysql-test/main/join.test
@@ -1820,3 +1820,18 @@ drop table t1,t2,t3;
 drop table t1000,t10,t03;
 
 --echo # End of 10.3 tests
+
+--echo #
+--echo # MDEV-30080 Wrong result with LEFT JOINs involving constant tables
+--echo #
+
+CREATE TABLE t1 (a INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 (b INT) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1),(1);
+CREATE TABLE t3 (c INT PRIMARY KEY) ENGINE=MyISAM;
+SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b = t3.c) ON t1.a = t2.b;
+SELECT COUNT(*) FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b = t3.c) ON t1.a = t2.b;
+DROP TABLE t1, t2, t3;
+
+--echo # End of 10.5 tests
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 98d5ccb7eb2..7bbe5c6a237 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -5639,7 +5639,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
             caller to abort with a zero row result.
           */
           TABLE_LIST *emb= s->table->pos_in_table_list->embedding;
-          if (emb && !emb->sj_on_expr)
+          if (emb && !emb->sj_on_expr && !*s->on_expr_ref)
           {
             /* Mark all tables in a multi-table join nest as const */
             mark_join_nest_as_const(join, emb, &found_const_table_map,