我有两个表：
1:
id | name
1 | test
2 | test1
2.
id | related_id | additional
1 | 1 | 1
2 | 1 | 2
1个表中的id与2个中的related_id相关
如何在没有复制记录的情况下将1个表与2个表联接，因此结果将仅为第二个表中的1行（related_id和additional可以是任何）
id | name | related_id | additional
1 | test | 1 | 1
2 | test1| NULL | NULL
更新如果我尝试在INNER/LEFT JOIN之后分组，结果是
id | name | related_id | additional
1 | test | 1 | 1
您可以使用主键对结果进行分组
select *
from table1 left join table2
on table1.id = table2.related_id
group by table1.id
您可以使用加入
SELECT
*
FROM table1 as t1
LEFT JOIN (
SELECT
MAX(id),
related_id
FROM table2
) as t2
ON t1.id = t2.related_id