Re: how to optimize this sql?

[h h]

root@localhost:legend 10:58:18> Show Create Table legend_account_coupon\G
*************************** 1. row ***************************
Table: legend_account_coupon
Create Table: CREATE TABLE `legend_account_coupon` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT '主键',
`is_deleted` char(1) NOT NULL DEFAULT 'N' COMMENT '删除标记',
`gmt_create` datetime NOT NULL DEFAULT '1970-01-01 00:00:00' COMMENT '创建时间',
`gmt_modified` datetime NOT NULL DEFAULT '1970-01-01 00:00:00' COMMENT '修改时间',
`creator` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '创建人',
`modifier` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '修改人',
`shop_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '门店ID',
`coupon_code` varchar(45) DEFAULT NULL COMMENT '优惠劵码',
`coupon_source` tinyint(3) unsigned DEFAULT NULL COMMENT '来源：0充值1赠送',
`effective_date` datetime DEFAULT NULL COMMENT '生效时间',
`expire_date` datetime DEFAULT NULL COMMENT '失效时间',
`used_status` tinyint(3) unsigned DEFAULT '0' COMMENT '是否使用0未使用1已使用',
`account_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '账户ID',
`coupon_info_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '优惠劵ID',
`coupon_type` tinyint(3) unsigned NOT NULL DEFAULT '0' COMMENT '优惠劵类型,0:折扣卷;1:现金券;2:通用券',
`coupon_name` varchar(45) NOT NULL DEFAULT '' COMMENT '优惠劵名称',
`suite_id` int(10) unsigned DEFAULT NULL COMMENT '来源某个套餐',
`flow_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '充值流水id',
`flow_sn` varchar(50) NOT NULL DEFAULT '' COMMENT '流水号',
`operator_name` varchar(50) DEFAULT NULL COMMENT '操作人名字',
PRIMARY KEY (`id`),
KEY `idx_accid` (`account_id`),
KEY `idx_coupid` (`coupon_info_id`)
) ENGINE=InnoDB AUTO_INCREMENT=609450 DEFAULT CHARSET=utf8 COMMENT='账户优惠劵表'
1 row in set (0.00 sec)

root@localhost:legend 10:58:24>select count(*) from legend_account_coupon\G
*************************** 1. row ***************************
count(*): 609449
1 row in set (0.43 sec)

root@localhost:legend 10:59:04>select count(distinct(coupon_info_id)) from legend_account_coupon\G
*************************** 1. row ***************************
count(distinct(coupon_info_id)): 1611
1 row in set (0.18 sec)

root@localhost:legend 10:59:21>select version();
+------------+
| version() |
+------------+
| 5.5.18-log |
+------------+
1 row in set (0.00 sec)

root@localhost:legend 10:59:48>show variables like '%pool%';
+---------------------------------+------------+
| Variable_name | Value |
+---------------------------------+------------+
| innodb_additional_mem_pool_size | 8388608 |
| innodb_buffer_pool_instances | 1 |
| innodb_buffer_pool_size | 5368709120 |
+---------------------------------+------------+

root@localhost:legend 11:00:09>\! free -m
total used free shared buffers cached
Mem: 7869 7668 200 0 179 1518
-/+ buffers/cache: 5970 1898
Swap: 0 0 0