我有一对多表 Payment
和 PaymentFlows
来跟踪付款工作流程。
对于不同的管理者,他们只对某些工作流程感兴趣。因此,每当付款达到某个工作流程时,就会向他们提供一个列表。
例如,
Payment 1 - A) Apply
B) Checked
C) Approved by Manager
D) Approved by CFO
E) Cheque issued
Payment 2 - A) Apply
B) Checked
C) Approved by Manager
Payment 3 - A) Apply
B) Checked
C) Approved by Manager
Payment 4 - A) Apply
B) Checked
要显示工作流程C
中的所有付款,我所做的是:
class Payment < ActiveRecord::Base
def self.search_by_workflow(flow_code)
self.find_by_sql("SELECT * FROM payments P INNER JOIN (
SELECT payment_id FROM (
SELECT * FROM (
SELECT * FROM payment_flows F
ORDER BY F.payment_flow_id DESC
) latest GROUP BY payment_id
) flows WHERE flows.code = flow_code)
) IDs ON IDs.payment_id = P.payment_id ORDER BY P.payment_id DESC LIMIT 100;")
end
end
所以:
@payments = Payment.search_by_workflow('Approved by Manager')
返回:付款 2
和 3
但是,性能不是很好(15,000 笔付款和 55,000 个工作流程需要 5 到 7 秒)。
如何提高性能?
更新(使用表结构):
CREATE TABLE `payments` (
`payment_id` int(11) NOT NULL,
`payment_type_code` varchar(50) default 'PETTY_CASH',
`status` varchar(16) NOT NULL default '?',
PRIMARY KEY (`payment_id`),
KEY `status` (`status`),
KEY `payment_type_code` (`payment_type_code`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `payment_flows` (
`payment_flow_id` int(11) NOT NULL,
`payment_id` int(11) default NULL,
`code` varchar(64) default NULL,
`status` varchar(255) NOT NULL default 'new',
PRIMARY KEY (`payment_flow_id`),
KEY `payment_id` (`payment_id`),
KEY `code` (`code`),
KEY `status` (`status`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
更新(使用name_scope
):
named_scope :by_workflows, lambda { |workflows| { :conditions => [ "EXISTS (
SELECT 'FLOW'
FROM payment_flows pf
WHERE pf.payment_id = payments.payment_id
AND pf.proc_code IN (:flows)
AND NOT EXISTS (
SELECT 'OTHER'
FROM payment_flows pfother
WHERE pfother.payment_id = pf.payment_id
AND pfother.payment_flow_id > pf.payment_flow_id
)
)", { :flows => workflows } ]}
}
为了方便,例如:
Payment.by_workflows(['Approved by Manager', 'Approved by CFO']).count
最佳答案
试试这个:
SELECT * FROM payment p
WHERE EXISTS(
SELECT 'FLOW'
FROM payment_flows pf
WHERE pf.payment_id = p.payment_id
AND pf.code = flow_code
AND NOT EXISTS(
SELECT 'OTHER'
FROM payment_flows pf2
WHERE pf2.payment_id = pf.payment_id
AND pf2.payment_flow_id > pf.payment_flow_id
)
)
注意:查询中的flow_code是一个变量,其中包含您要搜索的代码
我添加了一个关于 flow_code 是否存在的主要 EXISTS 条件,以及一个关于 flow_code 接下来不存在相同付款的其他 id 的嵌套 NOT EXISTS 条件。
告诉我是否可以提高性能。
关于mysql - 如何优化这个SELECT?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/36739997/