从mysql中的表中删除选定的行

Question

从表中删除此选择结果的最佳方法是什么？

select id from taxon2 as a 
   where rank = 'No Taxon' and 
   (select count(*) from taxon2 as b 
      where a.id = b.parentid) = 0;

Answer 1

以下是OUTER JOIN：

的解决方案

delete taxon2 
from taxon2
  left join taxon2 t2 on taxon2.id = t2.parentid
where t2.id is null;

• SQL Fiddle Demo

使用NOT EXISTS：

delete from taxon2
where rank = 'No Taxon' 
   and not exists (
      select 1
      from (select * from taxon2) as b 
      where b.parentid=taxon2.id)

• More Fiddle