select (null or null),(null or 1),(null || 0),(-8 or 0);
举一反三
- 设有如下代码段 1 String s = null; 2 if ( s != null & s.length() > 0) 3 System.out.println("s != null & s.length() > 0"); 4 if ( s != null && s.length() > 0) 5 System.out.println("s != null & s.length() > 0"); 6 if ( s != null || s.length() > 0) 7 System.out.println("s != null & s.length() > 0"); 8 if ( s != null | s.length() > 0) 9 System.out.println("s != null | s.length() > 0"); 哪些行将抛出空指针异常?
- 设有如下代码段 1 String s = null; 2 if ( s != null & s.length() > 0) 3 System.out.println("s != null & s.length() > 0"); 4 if ( s != null && s.length() > 0) 5 System.out.println("s != null & s.length() > 0"); 6 if ( s != null || s.length() > 0) 7 System.out.
- select (NULL<=>NULL) is NULL;的结果为_____
- 在SQL语句中，以下表达式值为“1”的是______。: NULL is NULL/#/NULL is not NULL/#/NULL=NULL/#/NULL！=NULL
- select (NULL<=>NULL) is NULL的;