mysql> select * from lugzer;
+------+------+------+
| row1 | row2 | row3 |
+------+------+------+
|    3 |    2 |    5 |
|    5 |   23 |    6 |
|    5 |    3 |   56 |
|   32 |    3 |   14 |
+------+------+------+
4 rows in set (0.00 sec)

mysql> SELECT LEAST(row1, row2, row3) FROM lugzer;
+-------------------------+
| LEAST(row1, row2, row3) |
+-------------------------+
|                       2 |
|                       5 |
|                       3 |
|                       3 |
+-------------------------+
4 rows in set (0.00 sec)

mysql>