我table_1有唯一的ID记录和多列数据
和
table_2有多行涉及特定ID和多列。 table2中的一列是，例如，time_lapse。
我需要保存所有列的两个表，但只有table2中具有最高time_lapse值的行。
我是这样尝试的......
create table as new_table
select table1.*, table2.* from
table1 left join table2
on table1.id=table2.id
where time_lapse=
(select max(time_lapse) from table2
group by id);
......但它失败了。
对新手的任何建议？谢谢。
答案 0 :(得分：0)
你很亲密。但是，您选择time_lapse每id个time_lapse，然后您就像只选择了一个只有一个IN的记录一样。使用id并在子查询的选择列表中添加create table as new_table
select table1.*, table2.* from
table1 left join table2
on table1.id=table2.id
where (table2.id, table2.time_lapse) in
(select id, max(time_lapse) from table2
group by id);
：
WHERE然后你在外部加入table2，但是在create table as new_table
select t1.*, t2.*
from table1 t1
left join table2 t2 on t1.id = t2.id
and (t2.id, t2.time_lapse) in
(select id, max(time_lapse) from table2 group by id);
子句中想要它的某些标准。这不起作用（因为外连接记录中的列为空）。
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