我的查询是针对库存表.子查询连接的作用是获取每个库存资产的工作订单总数.如果我使用设备类型,供应商,位置和房间的主连接运行基本查询,它运行正常.返回结果不到一秒钟.将它与子查询连接一起使用,返回结果需要15到20秒.
这是完整的查询:
SELECT `inventory`.inventory_id AS 'inventory_id',
`inventory`.media_tag AS 'media_tag',
`inventory`.asset_tag AS 'asset_tag',
`inventory`.idea_tag AS 'idea_tag',
`equipTypes`.equipment_type AS 'equipment_type',
`inventory`.equip_make AS 'equip_make',
`inventory`.equip_model AS 'equip_model',
`inventory`.equip_serial AS 'equip_serial',
`inventory`.sales_order AS 'sales_order',
`vendors`.vendor_name AS 'vendor_name',
`inventory`.purchase_order AS 'purchase_order',
`status`.status AS 'status',
`locations`.location_name AS 'location_name',
`rooms`.room_number AS 'room_number',
`inventory`.notes AS 'notes',
`inventory`.send_to AS 'send_to',
`inventory`.one_to_one AS 'one_to_one',
`enteredBy`.user_name AS 'user_name',
from_unixtime(`inventory`.enter_date, '%m/%d/%Y') AS 'enter_date',
from_unixtime(`inventory`.modified_date, '%m/%d/%Y') AS 'modified_date',
COALESCE(at.assets,0) AS assets
FROM mod_inventory_data AS `inventory`
LEFT JOIN mod_inventory_equip_types AS `equipTypes`
ON `equipTypes`.equip_type_id = …mysql ×1