mybatis sql部分優化
阿新 • • 發佈：2018-04-09
tis clust user name index let date join delete
1.先篩選出符合條件的再進行join,而不是先全表join再篩選
2.加入關鍵選項的索引
3.減少字段映射
4.左連接代替循環查詢,即盡量一次性查出
SELECT
a.name,a.uuid,a.app_name,a.app_uuid,a.release_uuid,a.release_name,
a.layout_template_name,a.layout_template_uuid,a.layout_template_version,
a.cluster_uuid,a.status,a.remark,a.delete_flag,
a.create_time,a.create_user,a.update_time,a.update_user,
d.department_code,d.deploy_type,d.department_name,d.namespace
FROM (
select * from app_instance where delete_flag=0
ORDER BY create_time desc LIMIT 1,2
) as a
LEFT JOIN dms_release as d
ON a.release_uuid = d.uuid
AND d.delete_flag=0
ALTER TABLE app_instance ADD INDEX index_release_uuid (release_uuid)
mybatis sql部分優化