假设如果我们提供了一个用于填充LPAD()或RPAD()函数的空字符串,则MySQL将返回NULL作为输出。以下示例将演示它-
mysql> Select LPAD('ABCD',22,'');
+--------------------+
| LPAD('ABCD',22,'') |
+--------------------+
| NULL |
+--------------------+
1 row in set (0.00 sec)
mysql> Select RPAD('ABCD',22,'');
+--------------------+
| RPAD('ABCD',22,'') |
+--------------------+
| NULL |
+--------------------+
1 row in set (0.00 sec)