diff --git a/mysql-test/r/type_datetime.result b/mysql-test/r/type_datetime.result
index ffe4bac142d..2a5d306cb23 100644
--- a/mysql-test/r/type_datetime.result
+++ b/mysql-test/r/type_datetime.result
@@ -427,6 +427,15 @@ f1
 Warnings:
 Warning	1292	Incorrect datetime value: '2007010100000' for column 'f1' at row 1
 drop table t1;
+create table t1 (f1 time);
+insert into t1 set f1 = '45:44:44';
+insert into t1 set f1 = '15:44:44';
+select * from t1 where (convert(f1,datetime)) != 1;
+f1
+15:44:44
+Warnings:
+Warning	1292	Incorrect datetime value: '0000-00-00 45:44:44'
+drop table t1;
 set @org_mode=@@sql_mode;
 create table t1 (da date default '1962-03-03 23:33:34', dt datetime default '1962-03-03');
 Warnings:
diff --git a/mysql-test/t/type_datetime.test b/mysql-test/t/type_datetime.test
index d8d137d81e6..b02fc1a9af0 100644
--- a/mysql-test/t/type_datetime.test
+++ b/mysql-test/t/type_datetime.test
@@ -283,6 +283,16 @@ select * from t1 where f1 between 2002010 and 20070101000000;
 select * from t1 where f1 between 20020101 and 2007010100000;
 drop table t1;
 
+#
+# Bug #31253: crash comparing datetime to double
+# Should return 1st row only. Crashes if NULL propagation fails.
+#
+create table t1 (f1 time);
+insert into t1 set f1 = '45:44:44';
+insert into t1 set f1 = '15:44:44';
+select * from t1 where (convert(f1,datetime)) != 1;
+drop table t1;
+
 #
 # Test of storing datetime into date fields
 #
diff --git a/sql/item.cc b/sql/item.cc
index d8080d62c39..dc94615c6e6 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -272,6 +272,7 @@ my_decimal *Item::val_decimal_from_date(my_decimal *decimal_value)
   if (get_date(&ltime, TIME_FUZZY_DATE))
   {
     my_decimal_set_zero(decimal_value);
+    null_value= 1;                               // set NULL, stop processing
     return 0;
   }
   return date2my_decimal(&ltime, decimal_value);