sql like语句通配符百分号、下划线与escape用法

# %代表任意多个字符 
select * from user where username like '%huxiao'; 
select * from user where username like 'huxiao%'; 
select * from user where username like '%huxiao%'; 
 
# %代表一个字符 
select * from user where username like '_';
select * from user where username like '______';
select * from user where username like 'huxia_';
select * from user where username like 'h_xiao'; 
 
# 要查%或者_，的话？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 '%xiao/_%' escape '/'; 
select username from gg_user where username like '%xiao/%%' escape '/';