In a sql like statement like
select * from user where username like '%nihao%'，select * from user where username like '_nihao',
Among them, % is used as a wildcard for multiple wildcards, and _ is used as a wildcard for one wildcard
If you really want to query usernames containing % _, you need to make them no longer as wildcards
Escape % _ in like, take _ as an example,
转义前：select * from user where username like '_nihao',
After escaping: select * from user where username like '/_nihao' escape '/', which means that the _ after / is not a wildcard