mysql 某一字段 手动实现自增

Question

查询一个字段的最大值 然后+1 再插入数据中
查到最大值+1

select max(sequence) +'1'
from
  make_sample_technology_process_product;

把最大值插入 id='7'的数据

update  
make_sample_technology_process_product
set sequence = ? where id='7'

这两句都可以用 加在一起就不行了

update  
make_sample_technology_process_product
set sequence =select max(sequence) +'1'
from
  make_sample_technology_process_product
where id = '7';

Answer 1

试试后面的子查询用括号括起来。

update  
make_sample_technology_process_product
set sequence = (select max(sequence) +'1'
from
  make_sample_technology_process_product
where id = '7');