diff --git a/mysql-test/r/func_misc.result b/mysql-test/r/func_misc.result
index 9f2fcb06638..f23718466d3 100644
--- a/mysql-test/r/func_misc.result
+++ b/mysql-test/r/func_misc.result
@@ -327,4 +327,19 @@ DROP TABLE t1;
 select NAME_CONST('_id',1234) as id;
 id
 1234
+#
+# Bug #54461: crash with longblob and union or update with subquery
+#
+CREATE TABLE t1 (a INT, b LONGBLOB);
+INSERT INTO t1 VALUES (1, '2'), (2, '3'), (3, '2');
+SELECT DISTINCT LEAST(a, (SELECT b FROM t1 LIMIT 1)) FROM t1 UNION SELECT 1;
+LEAST(a, (SELECT b FROM t1 LIMIT 1))
+1
+2
+SELECT DISTINCT GREATEST(a, (SELECT b FROM t1 LIMIT 1)) FROM t1 UNION SELECT 1;
+GREATEST(a, (SELECT b FROM t1 LIMIT 1))
+2
+3
+1
+DROP TABLE t1;
 End of 5.0 tests
diff --git a/mysql-test/t/func_misc.test b/mysql-test/t/func_misc.test
index 01c508c9b58..89359fab0ca 100644
--- a/mysql-test/t/func_misc.test
+++ b/mysql-test/t/func_misc.test
@@ -450,5 +450,16 @@ DROP TABLE t1;
 #
 select NAME_CONST('_id',1234) as id;
 
---echo End of 5.0 tests
+--echo #
+--echo # Bug #54461: crash with longblob and union or update with subquery
+--echo #
 
+CREATE TABLE t1 (a INT, b LONGBLOB);
+INSERT INTO t1 VALUES (1, '2'), (2, '3'), (3, '2');
+
+SELECT DISTINCT LEAST(a, (SELECT b FROM t1 LIMIT 1)) FROM t1 UNION SELECT 1;
+SELECT DISTINCT GREATEST(a, (SELECT b FROM t1 LIMIT 1)) FROM t1 UNION SELECT 1;
+
+DROP TABLE t1;
+
+--echo End of 5.0 tests
diff --git a/sql/item_func.cc b/sql/item_func.cc
index cb0d6bdbe5f..8af7db7fa1a 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -2250,6 +2250,8 @@ void Item_func_min_max::fix_length_and_dec()
   else if ((cmp_type == DECIMAL_RESULT) || (cmp_type == INT_RESULT))
     max_length= my_decimal_precision_to_length(max_int_part+decimals, decimals,
                                             unsigned_flag);
+  else if (cmp_type == REAL_RESULT)
+    max_length= float_length(decimals);
   cached_field_type= agg_field_type(args, arg_count);
 }