G(RAND(),3,2),DATE_ADD(NOW(),INTERVAL -SUBSTRING(RAND(),3,3) DAY),DATE_ADD(NOW(),INTERVAL -SUBSTRING(RAND(),3,2) DAY));
执行一次INSERT ** SELECT **语句：
INSERT INTO right_table
SELECT ID,SUBSTRING(RAND(),3,4) AS CollectNum,SUBSTRING(RAND(),3,2) AS BuyNum,SUBSTRING(RAND(),3,3) AS SearchNum,CreatDate,AlterDate
FROM left_table WHERE ID%5=1;
注释：表left_table将会有ID值1,2,3,***,10连续的记录10条，表right_table中有ID值1,6离散的记录2条，并且2表关联条件为：left_table.ID=right_table.UID实现。
对比测试
基准测试表中将可能看到的数据(编号：SQL_1)
root@localhost : eugene 03:25:07> SELECT M.ID,M.username FROM left_table M WHERE M.ID<=6;
+----+-----------------+
| ID | username |
+----+-----------------+
| 1 | 06440350@qq.com |
| 2 | 25173782@qq.com |
| 3 | 66328120@qq.com |
| 4 | 16752438@qq.com |
| 5 | 92117196@qq.com |
| 6 | 02026078@qq.com |
+----+-----------------+
标准左连接
ON字句中无连接字段之外条件的SQL及数据(编号：SQL_2)
root@localhost : eugene 03:37:58> SELECT M.ID,M.username,N.CollectNum,N.BuyNum
-> FROM left_table M LEFT JOIN right_table N ON M.ID=N.UID
-> WHERE M.ID<=6;
+----+-----------------+------------+--------+
| ID | username | CollectNum | BuyNum |
+----+-----------------+------------+--------+
| 1 | 06440350@qq.com | 817 | 39 |
| 2 | 25173782@qq.com | NULL | NULL |
|&n