参考答案: CD
详细解析:
A选项语法错误；BCD结果如图<img src="http://wei.edu360.cn/attachment/simple_images/20201106/8fb08a6943-15.png"><br>A. select concat(first_name,tab,last_name) from user_profile;
B. select first_name+'\t'+last_name from user_profile;
C. select concat(first_name,'\t',last_name) from user_profile;
D. select concat(first_name,chr(9),last_name) from user_profile;
参考答案: CD
详细解析:
A选项语法错误；BCD结果如图<img src="http://wei.edu360.cn/attachment/simple_images/20201106/8fb08a6943-15.png"><br>