SQL語句DML語句總結

查詢：

一、用一個表更新另外一個表SQL
UPDATE a,b set a.title = b.title where a.id = b.aid;
二、表中有多條數據取最新一條(子查詢解決方案)
//select * from (select * from `test` order by `date` desc) `temp`  group by product_code order by `date` desc  效率太慢