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如果我将NULL提供给MySQL的ASCII()函数,它会返回什么?

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2023-08-23 19:37:02969浏览

如果我将NULL提供给MySQL的ASCII()函数,它会返回什么?

在这种情况下,ASCII()函数的输出取决于我们是否将NULL作为字符串提供,还是仅仅提供NULL。以下示例将演示区别−

mysql> SELECT ASCII(null);
+-------------+
| ASCII(null) |
+-------------+
| NULL        |
+-------------+
1 row in set (0.00 sec)

mysql> SELECT ASCII('null');
+---------------+
| ASCII('null') |
+---------------+
| 110           |
+---------------+
1 row in set (0.00 sec)

mysql> Select ASCII(NULL);
+-------------+
| ASCII(NULL) |
+-------------+
| NULL        |
+-------------+
1 row in set (0.00 sec)

mysql> Select ASCII('NULL');
+---------------+
| ASCII('NULL') |
+---------------+
| 78            |
+---------------+
1 row in set (0.00 sec)

As we can observe from the above result set that when we will provide NULL or null as a string, ASCII() function will return the number code of the first character i.e. number code of N in case of ‘NULL’ and number code of n in case of ‘null’, otherwise when we provide simply NULL then it returns NULL as output.

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