Mysql根据前缀计算总内存
请在此表格中填写:Mysql根据前缀计算总内存,mysql,memory,byte,Mysql,Memory,Byte,请在此表格中填写: CREATE TABLE IF NOT EXISTS `assets` ( `asset_id` bigint(20) NOT NULL AUTO_INCREMENT, `asset_memory` varchar(255) NOT NULL, `asset_memory_prefix` tinyint(1) NOT NULL DEFAULT '2', PRIMARY KEY (`asset_id`), KEY `Locations` (`positio
CREATE TABLE IF NOT EXISTS `assets` (
`asset_id` bigint(20) NOT NULL AUTO_INCREMENT,
`asset_memory` varchar(255) NOT NULL,
`asset_memory_prefix` tinyint(1) NOT NULL DEFAULT '2',
PRIMARY KEY (`asset_id`),
KEY `Locations` (`position_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;
我需要根据
资产内存和资产内存前缀,其中资产内存前缀的定义如下:
$_prefix = array(
array("id" => 0, "prefix" => "B", "prefix_name" => "byte", "pow_value" => "0"),
array("id" => 1, "prefix" => "Kb", "prefix_name" => "Kilobyte", "pow_value" => "1"),
array("id" => 2, "prefix" => "Mb", "prefix_name" => "Megabyte", "pow_value" => "2"),
array("id" => 3, "prefix" => "Gb", "prefix_name" => "Gigabyte", "pow_value" => "3"),
array("id" => 4, "prefix" => "Tb", "prefix_name" => "Terabyte", "pow_value" => "4"),
array("id" => 5, "prefix" => "Pb", "prefix_name" => "Petabyte", "pow_value" => "5"),
array("id" => 6, "prefix" => "Eb", "prefix_name" => "Exabyte", "pow_value" => "6"),
array("id" => 7, "prefix" => "Zb", "prefix_name" => "Zettabyte", "pow_value" => "7")
);
因此,条目可能如下所示:
asset_id, asset_memory, asset_memory_prefix
1, 1024, 2
2, 1024, 3
3, 2048, 2
如何在SELECT中执行此操作?是否只需要一个群组
编辑:
我认为这就是您想要的,假设asset_memory_前缀是一个表:
select a.asset_id,
sum(pow(1000, ap.pow_value) * asset_memory) as total_memory_bytes
from assets a join
asset_prefix ap
on a.asset_memory_prefix = ap.asset_memory_prefix
group by a.asset_id;
我不确定你是要1000还是10242^10
您应该能够直接使用资产\内存\前缀:
select a.asset_id,
sum(pow(1024, ap.asset_memory_prefix) *
asset_memory
) as total_memory_bytes
from assets a join
asset_prefix ap
on a.asset_memory_prefix = ap.asset_memory_prefix
group by a.asset_id;
最后一个例子就是我需要的。我已将其设置为1024。但它只是PHP前缀中的一个数组,不在表中
select a.asset_id,
sum(pow(1024, ap.asset_memory_prefix) *
asset_memory
) as total_memory_bytes
from assets a join
asset_prefix ap
on a.asset_memory_prefix = ap.asset_memory_prefix
group by a.asset_id;