LEAST() returns NULL if any argument is NULL : LEAST « Comparison Functions Operators « MySQL Tutorial






mysql>
mysql> SELECT LEAST(2,NULL);
+---------------+
| LEAST(2,NULL) |
+---------------+
|          NULL |
+---------------+
1 row in set (0.00 sec)








15.11.LEAST
15.11.1.LEAST(value1,value2,...) returns the smallest (minimum-valued) argument withing two or more arguments
15.11.2.LEAST() returns NULL if any argument is NULL
15.11.3.LEAST with float value
15.11.4.Using LEAST with string value
15.11.5.Use LEAST with data in a table