GREATEST() 함수
With two or more areuments, returns the largest(maximim-values) argument. The arguments are compared using the same rules as for LEAST():
인자값으로 있는 것들 중에 가장 큰 값을 return 한다.
대소문자는 가리지 않는 것 같다.
mysql> SELECT GREATEST(2, 0);
+----------------+
| GREATEST(2, 0) |
+----------------+
| 2 |
+----------------+
1 row in set (0.00 sec)
mysql> SELECT GREATEST('B', 'A', 'C');
+-------------------------+
| GREATEST('B', 'A', 'C') |
+-------------------------+
| C |
+-------------------------+
1 row in set (0.00 sec)
mysql> SELECT GREATEST(100, 'A', 'C');
+-------------------------+
| GREATEST(100, 'A', 'C') |
+-------------------------+
| C |
+-------------------------+
1 row in set (0.00 sec)
mysql> SELECT GREATEST('aa', 'bb', 'C');
+---------------------------+
| GREATEST('aa', 'bb', 'C') |
+---------------------------+
| C |
+---------------------------+
1 row in set (0.00 sec)
mysql> SELECT GREATEST('aa', 'bb', 'c');
+---------------------------+
| GREATEST('aa', 'bb', 'c') |
+---------------------------+
| c |
+---------------------------+
1 row in set (0.00 sec)
mysql> SELECT GREATEST(NULL, 0);
+-------------------+
| GREATEST(NULL, 0) |
+-------------------+
| NULL |
+-------------------+
1 row in set (0.00 sec)
반면 가장 작은 값은 LEAST() 함수를 사용한다.