select (NULL<=>NULL) is NULL的;
举一反三
- 152.select (NULL<=>NULL) is NULL;的结果为_____。
- 下列选项中哪一个是正确的空值查询条件的SQL表达（ ） A: < >NULL B: !=NULL C: IS NOT NULL D: NOT IS NULL
- select (null or null),(null or 1),(null || 0),(-8 or 0);
- select (NULL<=>NULL) is NULL;的结果为_____
- 查询student表中的所有非空email信息, 以下语句正确的是（ ） A: Select email from student where email !=null B: Select email from student where email not is null C: Select email from student where email <> null D: Select email from student where email is not null