
转化为sql
SELECT COUNT( * ) FROM upgrade_record
WHERE (DATE_FORMAT(upgrade_apply_to_appointment_time,'%Y%m%d%H%i%S')>=DATE_FORMAT(NOW(),'%Y%m%d%H%i%S')
AND YEARWEEK(DATE_FORMAT(changed,'%Y%m%d')) = YEARWEEK(now())
AND (upgrade_apply_status = 'R' OR upgrade_apply_status = 'C'))
不懂怎么提高性能,求指教,谢谢了
1.对条件字段加索引
2.条件列尽量不要用函数
3.如果数据库特别大可以考虑按时间分区分表