我想知道如何优化sql查询。
表结构如下：
委员会：
+---------------------------+----------------------------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------------+----------------------------------------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| network_commission | int(11) | YES | | NULL | |
+---------------------------+----------------------------------------------+------+-----+---------+----------------+
AdvertiserBalanceTransactions ：
+---------------------+---------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------+---------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| commission_id | int(11) | YES | MUL | NULL | |
| transaction_type | varchar(255) | YES | | NULL | |
| amount | decimal(10,2) | YES | | 0.00 | |
| currency_code | varchar(3) | YES | | NULL | |
| created_at | datetime | NO | | NULL | |
| updated_at | datetime | NO | | NULL | |
+---------------------+---------------+------+-----+---------+----------------+
规则：
AdvertiserBalanceTransactions只能有两种类型：＆＃39; new_commissions＆＃39;或者＆＃39; nt_commission＆＃39;。类型＆＃39; new_commissions＆＃39;只有在'nt_commission＆＃39;可以出现n次（至少一次至多一次，具有不同的值）。
更新佣金表network_commission列：
network_commission以值NULL开头，并且必须使用以下表达式填充：第一个创建的类型为＆nt_commission＆＃39; nt_commission＆＃39;的AdvertiserBalanceTransaction的值（金额）。 * 100 /类型＆＃39; new_commission＆＃39;的AdvertiserBalanceTransaction的值（金额）。
以下查询执行此操作：
update commissions set commissions.network_commission=(
select t.amount * 100 / new_com_tran.amount
from advertiser_balance_transactions new_com_tran,
(select nt_com_tran.amount, nt_com_tran.commission_id
from advertiser_balance_transactions nt_com_tran
where nt_com_tran.transaction_type = 'nt_commission'
order by created_at asc limit 1) t
where commissions.id=new_com_tran.commission_id
AND new_com_tran.transaction_type = 'new_commissions'
AND t.commission_id=commissions.id)
where commissions.amount != 0;
示例数据：
佣金：
+--------+--------------------+
| id | network_commission |
+--------+--------------------+
| 887755 | NULL |
| 887752 | NULL |
| 887751 | NULL |
| 887750 | NULL |
| 887749 | NULL |
| 887748 | NULL |
| 887747 | NULL |
| 887746 | NULL |
| 887745 | NULL |
| 887744 | NULL |
+--------+--------------------+
AdvertiserBalanceTransactions：
+---------+---------------+------------------+--------+---------------+---------------------+---------------------+
| id | commission_id | transaction_type | amount | currency_code | created_at | updated_at |
+---------+---------------+------------------+--------+---------------+---------------------+---------------------+
| 1432047 | 887744 | new_commissions | -0.30 | RON | 2018-01-22 09:09:54 | 2018-01-22 09:09:54 |
| 1432048 | 887744 | nt_commission | -0.12 | RON | 2018-01-22 09:09:54 | 2018-01-22 09:09:54 |
| 1432048 | 887744 | nt_commission | -0.23 | RON | 2018-01-22 09:10:54 | 2018-01-22 09:10:54 |
| 1432049 | 887745 | new_commissions | -0.30 | RON | 2018-01-22 09:09:57 | 2018-01-22 09:09:57 |
| 1432050 | 887745 | nt_commission | -0.12 | RON | 2018-01-22 09:09:57 | 2018-01-22 09:09:57 |
| 1432051 | 887746 | new_commissions | -0.30 | RON | 2018-01-22 11:06:23 | 2018-01-22 11:06:23 |
| 1432052 | 887746 | nt_commission | -0.12 | RON | 2018-01-22 11:06:23 | 2018-01-22 11:06:23 |
| 1432053 | 887747 | new_commissions | -0.30 | RON | 2018-01-22 11:09:35 | 2018-01-22 11:09:35 |
| 1432054 | 887747 | nt_commission | -0.12 | RON | 2018-01-22 11:09:35 | 2018-01-22 11:09:35 |
| 1432055 | 887748 | new_commissions | -0.30 | RON | 2018-01-22 11:11:09 | 2018-01-22 11:11:09 |
| 1432056 | 887748 | nt_commission | -0.12 | RON | 2018-01-22 11:11:09 | 2018-01-22 11:11:09 |
| 1432057 | 887749 | new_commissions | -0.30 | RON | 2018-01-22 11:19:10 | 2018-01-22 11:19:10 |
| 1432058 | 887749 | nt_commission | -0.12 | RON | 2018-01-22 11:19:10 | 2018-01-22 11:19:10 |
| 1432059 | 887750 | new_commissions | -0.30 | RON | 2018-01-22 11:22:21 | 2018-01-22 11:22:21 |
| 1432060 | 887750 | nt_commission | -0.12 | RON | 2018-01-22 11:22:21 | 2018-01-22 11:22:21 |
| 1432061 | 887751 | new_commissions | -0.30 | RON | 2018-01-23 10:29:48 | 2018-01-23 10:29:48 |
| 1432062 | 887751 | nt_commission | -0.12 | RON | 2018-01-23 10:29:48 | 2018-01-23 10:29:48 |
| 1432063 | 887752 | new_commissions | -0.30 | RON | 2018-01-23 12:55:11 | 2018-01-23 12:55:11 |
| 1432064 | 887752 | nt_commission | -0.12 | RON | 2018-01-23 12:55:11 | 2018-01-23 12:55:11 |
| 1432069 | 887755 | new_commissions | -2.10 | RON | 2018-02-22 11:38:45 | 2018-02-22 11:38:45 |
| 1432070 | 887755 | nt_commission | -0.84 | RON | 2018-02-22 11:38:45 | 2018-02-22 11:38:45 |
+---------+---------------+------------------+--------+---------------+---------------------+---------------------+
无论如何我可以优化此更新查询吗？
答案 0 :(得分：1)
我建议使用JOINS
update commissions c
LEFT JOIN advertiser_balance_transactions new_t
ON c.id=new_t.commission_id AND new_t.transaction_type='new_commissions'
LEFT JOIN advertiser_balance_transactions first_nt_t
ON c.id=first_nt_t.commission_id AND first_nt_t.transaction_type='nt_commission'
AND first_nt_t.created_at=(SELECT MIN(created_at)
FROM advertiser_balance_transactions t3
WHERE t3.commission_id=c.id AND transaction_type='nt_commission')
set commissions.network_commission = first_nt_t.amount * 100 / new_t.amount
答案 1 :(得分：0)
你可以 JOIN 将两个选择合二为一，根据你的DBMS甚至完全消除选择，因为一些（例如SYBASE）允许 FROM 中的多个表。