sql语句的意思还有运行后的效果

Question

mysql> select sno||","||sname||","||sex||","||dept||","||birth||","||age
-> "out_put" from student;

    上面的语句运行后的结果如下：
    请问大神们，这是什么意思？？？？？？在线等~~~0.0

+---------+
| out_put |
+---------+
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
| 1 |
+---------+
12 rows in set (0.00 sec)

Answer 1

两条竖线在MySQL中是逻辑or，在Oracle中是连接字符串。所以你这个执行结果是1。因为字符串作为bool表达式是true