Unknown column 'shouye3' in 'where clause'

String sql = "select allow_pic,allow_text,allow_link,price from ad_module where alias= shouye3；

报出Unknown column 'shouye3' in 'where clause'的错误

原因是：alias是字符类型的数据，查找应该加上引号。改成

select allow_pic,allow_text,allow_link,price from ad_module where alias='shouye3'就不会报错了