调试易

语句本身没什么可优化的了。关键看你的索引是否创建了。explain SELECT COUNT(*) FROM backlinkurl LEFT JOIN urlinformation ON (backlinkurl.urlrank=urlinformation.urlid AND backlinkurl.keywordid=urlinformation.keywordid);show index from backlinkurl;
show index from urlinformation;贴出来看一下。

index of backlinkurl is id( primary)
index of urlinformation is also id( primary)

再把urlrank　urlid　keywordid　keywordid　设为index,效果好多了

请如下直接贴你的结果！mysql> show index from table1;
+--------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table  | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+--------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| table1 |          0 | PRIMARY  |            1 | id          | A         |      3 |     NULL | NULL   |      | BTREE      |         |
+--------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
1 row in set (0.14 sec)mysql>

大大 你的
+--------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table  | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+--------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| table1 |          0 | PRIMARY  |            1 | id          | A         |      3 |     NULL | NULL   |      | BTREE      |         |
+--------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
1 row in set (0.14 sec)
这个是从DOS里面黏贴过来的还是哪个工具上来的？

一般我们的索引键在联接字段 分组字段 排序字段和 where条件筛选字段

你这个到底是统计什么啊，如果要是统计两表相同的数据，用inner join

LZ的意思是两张表，除了PK，就没有index了？？？！！！