DESC select a.id,rkno,a.packageno as packageno,cust_no,lotno,count(*) as count from `rk_record` as a right join `sys_barcode_1d_y` as b on a.packageno = b.packageno where rkno = '201401030031' group by packageno,lotno order by packageno,lotno asc查看哪一个地方,查询慢,合理优化表结构和索引。
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE b ALL NULL NULL NULL NULL 410226 Using temporary; Using filesort
1 SIMPLE a ref rkno,packageno packageno 92 func 1 Using where是不是b表没有限制条件导致查询变慢?
写作 b.packageno = a.packageno