Question

我有两张桌子

table1: { id, name }
table2: { id, table1_id, time_added }

可以在一个查询中只获取表2中所有项目中最后添加的相关项目吗？

Answer 1

这将有效：

SELECT
  t1.*,
  t2.*
FROM Table1 t1
INNER JOIN table2 t2 on t2.table1_id = t1.id
INNER JOIN (SELECT Max(time_added) as time_added, table1_id FROM Table2 Group by table1_id) t2a on 
    t2a.time_added = t2.time_added AND t2a.table1_id = t2.table1_id

Answer 2

SELECT table1.id，table1.name FROM table1 JOIN table2 ON table1.id = table2.id GROUP BY table2.id ORDER BY time_added DESC;

这是你的答案，如果你需要澄清，请告诉我。

Answer 3

选择表2中最后添加的项目非常简单。

SELECT * FROM TABLE1 AS tb1 WHERE tb1.id IN (SELECT MAX(id) FROM TABLE2)

注意：在上面的查询中，table1的id和table2的id必须是AUTO INCREMENTED。

尝试以上查询。

谢谢！

Answer 4

使用此解决方案，您不需要子查询... 基于ajacian81

SELECT table1.*, table2.* 
FROM table1 LEFT JOIN table2 
    ON table1.id = table2.table1_id 
GROUP BY table1.id 
ORDER BY table2.time_added DESC;

MySQL查询获取单个项目和最新关联项目

4 个答案: