CC_AGE check (length(name)>2);
增加/删除unique key
ALTER TABLE Persons
ADD CONSTRAINT uc_PersonID UNIQUE...索引冲突, 则忽略当前新数据,但不会出现错误
insert into ... ...使用escape,转义字符后面的%或_就不作为通配符了,注意前面没有转义字符的%和_仍然起通配符作用
select username from gg_user where username like..., count(distinct url, get_keys, post_keys) from sec_tmp_after_task1_step10 group by url, get_keys, post_keys...select url, get_keys, post_keys, wm_concat(distinct url_source, ",", "asc") as url_source_all from