一、查询SQL尽量不要使用select *，而是具体字段。1、反例select * from CUSTOM_CABINETS22、正例select STATE,CLASSIFY,CABINETS_TWO_CODE,cabinets_two_type from CUSTOM_CABINETS23、理由节省资源、减少网络开销。可能用到覆盖索引，减少回表，提高查询效率。二、where中....

文章 2022-10-17 来自：开发者社区

说说对SQL语句优化有哪些方法？

说说对SQL语句优化有哪些方法？（1）Where子句中：where表之间的连接必须写在其他Where条件之前，那些可以过滤掉最大数量记录的条件必须写在Where子句的末尾.HAVING最后。（2）用EXISTS替代IN、用NOT EXISTS替代NOT IN。（3）避免在索引列上使用计算（4）避免在索引列上使用IS NUL....

文章 2022-05-29 来自：开发者社区

1.JAVA基础面试常考问题： JAVA面试基础常考题汇集2.JAVA面试SSM框架常考：JAVA框架面试题汇集1.对查询进行优化，要尽量避免全表扫描，首先应考虑在where及order by涉及的列上建立索引。ps：能用索引查的可以考虑用索引2.应尽量避免在where句中对字段进行null值判断，否则将导致引擎放弃使用索引而进行全表扫描，如:select id from t where n....

文章 2022-05-20 来自：开发者社区

几个必须掌握的SQL优化技巧(六)：针对SQL语句的优化

1 前言在应用的开发过程中，由于开发初期的数据量一般都比较小，所以开发过程中一般都比较注重功能上的实现，但是当完成了一个应用或者系统之后，随着生产数据量的急剧增长，那么之前的很多sql语句的写法就会显现出一定的性能问题，对生产的影响也会越来越大，这些不恰当的sql语句就会成为整个系统性能的瓶颈，为了追求系统的极致性能，必须要对它们进行优化。2 正文前面几篇文章主要介绍了如何通过一些命令来分析sq....

问答 2021-12-12 来自：开发者社区

怎样可以让SQL语句优化？

共有28条

< 1 2 3 >

跳转至： GO

更新时间 2024-09-13 11:01:07

本页面内关键词为智能算法引擎基于机器学习所生成，如有任何问题，可在页面下方点击"联系我们"与我们沟通。

SQL语句相关内容

SQL更多语句相关

SQL您可能感兴趣

产品推荐

{"moduleinfo":{"card_count":[{"count_phone":1,"count":1}],"search_count":[{"count_phone":4,"count":4}]},"card":[{"des":"云数据库SQL Server，具有企业许可授权，权限更为开放，引擎功能更为强大。能完美支持Windows平台的.NET架构，支持复杂SQL查询，性能优秀，并有强大的可视化管理工具，帮助您轻松管理数据。","link1":"https://rdsnew.console.aliyun.com/console/buy#/create/rds?initData=%7B%22data%22:%7B%22rds_region%22:%22cn-hangzhou%22,%22rds_dbtype%22:%22mssql%22,%22rds_dbversion%22:%222016_web%22,%22rds_web_type%22:%221%22,%22rds_class%22:%22mssql.x2.medium.w1%22,%22rds_storage%22:%2220%22,%22duration%22:12%7D%7D","link":"https://www.aliyun.com/product/rds/sqlserver","icon":"https://img.alicdn.com/tfs/TB1kuYmv3mTBuNjy1XbXXaMrVXa-200-200.png","btn2":"2016 标准版","tip":"完美兼容windows操作系统，已通过ISO 20000、SOC、PCI-DSS、等保三级等十项安全合规认证。         最新产品和实时动态重磅发布<a href=\"https://www.aliyun.com/product/new?source_type=out_sousuo_feature_0716\" target=\"_blank\">立即查看</a>","btn1":"2016 Web版","link2":"https://rdsnew.console.aliyun.com/console/buy#/create/rds?initData=%7B%22data%22:%7B%22rds_region%22:%22cn-shanghai%22,%22rds_dbtype%22:%22mssql%22,%22rds_dbversion%22:%222016_std_ha%22,%22rds_web_type%22:%221%22,%22rds_class%22:%22mssql.x4.medium.s2%22,%22rds_storage%22:%2220%22,%22duration%22:12%7D%7D","title":"云数据库RDS SQL Server版"}],"search":[{"txt":"SQL Server Web版","link":"https://promotion.aliyun.com/ntms/act/sqlserverweb.html"},{"txt":"SQL Server 标准版/企业版","link":"https://promotion.aliyun.com/ntms/act/sqlservergaokeyong.html"},{"txt":"快速入门SQL Server","link":"https://help.aliyun.com/document_detail/26141.html"},{"txt":"产品动态","link":"https://www.aliyun.com/product/new?source_type=out_sousuo_feature_0716"}],"countinfo":{"search":{"length_pc":0,"length":0},"card":{"length_pc":0,"length":0}},"simplifiedDisplay":"newEdition","newCard":[{"link":"https://www.aliyun.com/product/rds/sqlserver","title":"云数据库 RDS SQL Server 版","des":"云数据库SQL Server，具有企业许可授权，权限更为开放，引擎功能更为强大。能完美支持Windows平台的.NET架构，支持复杂SQL查询，性能优秀，并有强大的可视化管理工具，帮助您轻松管理数据。","btn1":"产品详情","link1":"https://www.aliyun.com/product/rds/sqlserver","btn2":"管理控制台","link2":"https://rdsnext.console.aliyun.com/#/rdsList/cn-hangzhou/basic/","link3":"https://www.aliyun.com/core/online-consult?from=OVtXEBmlH8","btn3":"在线咨询","infoGroup":[{"infoName":"最新活动","infoContent":{"firstContentName":"新用户年付低至3折起","firstContentLink":"https://www.aliyun.com/activity/database/bestoffers","lastContentName":"2核4GB 299元/年","lastContentLink":"https://rdsbuy.console.aliyun.com/newCreate/rds/mssql?initData={\"data\":{\"rds_dbtype\":\"\tmssql\",\"rds_dbversion\":\"2022_web\",\"rds_web_type\":\"1\",\"rds_class\":\"mssql.share2.medium.w1\",\"rds_storage\":\"100\",\"rds_nodetype\":\"Basic\",\"duration\":12,\"rds_storagetype\":\"cloud_auto\",\"rds_arch\":\"X86\"}}"}},{"infoName":"快速入门","infoContent":{"firstContentName":"帮助文档","firstContentLink":"https://help.aliyun.com/product/26090.html","lastContentName":"入门指南","lastContentLink":"https://help.aliyun.com/document_detail/53729.htm"}},{"infoName":"产品动态","infoContent":{"firstContentName":"存储能力全方位升级","firstContentLink":"https://www.aliyun.com/activity/database/rds-storage-upgrade","lastContentLink":"https://help.aliyun.com/zh/rds/bi-monthly-product-report-for-apsaradb-rds-march-april-2025-2","lastContentName":"RDS 产品双月报"}},{"infoName":"客户案例","infoContent":{"firstContentName":"RDS 助力巴黎奥运会系统稳定运行","firstContentLink":"https://help.aliyun.com/zh/rds/apsaradb-rds-for-sql-server/apsaradb-rds-helps-ensure-the-stability-of-the-system-of-the-paris-olympic-games","lastContentName":"","lastContentLink":""}}],"icon":"","ifIcon":"img","iconImg":"https://img.alicdn.com/tfs/TB1FIpvn3gP7K4jSZFqXXamhVXa-200-200.png","contentLink":"https://www.aliyun.com/product/rds/sqlserver"}]}

{"$env":{"JSON":{}},"$page":{"env":"production"},"$context":{"moduleinfo":{"card_count":[{"count_phone":1,"count":1}],"search_count":[{"count_phone":4,"count":4}]},"card":[{"des":"云数据库SQL Server，具有企业许可授权，权限更为开放，引擎功能更为强大。能完美支持Windows平台的.NET架构，支持复杂SQL查询，性能优秀，并有强大的可视化管理工具，帮助您轻松管理数据。","link1":"https://rdsnew.console.aliyun.com/console/buy#/create/rds?initData=%7B%22data%22:%7B%22rds_region%22:%22cn-hangzhou%22,%22rds_dbtype%22:%22mssql%22,%22rds_dbversion%22:%222016_web%22,%22rds_web_type%22:%221%22,%22rds_class%22:%22mssql.x2.medium.w1%22,%22rds_storage%22:%2220%22,%22duration%22:12%7D%7D","link":"https://www.aliyun.com/product/rds/sqlserver","icon":"https://img.alicdn.com/tfs/TB1kuYmv3mTBuNjy1XbXXaMrVXa-200-200.png","btn2":"2016 标准版","tip":"完美兼容windows操作系统，已通过ISO 20000、SOC、PCI-DSS、等保三级等十项安全合规认证。         最新产品和实时动态重磅发布<a href=\"https://www.aliyun.com/product/new?source_type=out_sousuo_feature_0716\" target=\"_blank\">立即查看</a>","btn1":"2016 Web版","link2":"https://rdsnew.console.aliyun.com/console/buy#/create/rds?initData=%7B%22data%22:%7B%22rds_region%22:%22cn-shanghai%22,%22rds_dbtype%22:%22mssql%22,%22rds_dbversion%22:%222016_std_ha%22,%22rds_web_type%22:%221%22,%22rds_class%22:%22mssql.x4.medium.s2%22,%22rds_storage%22:%2220%22,%22duration%22:12%7D%7D","title":"云数据库RDS SQL Server版"}],"search":[{"txt":"SQL Server Web版","link":"https://promotion.aliyun.com/ntms/act/sqlserverweb.html"},{"txt":"SQL Server 标准版/企业版","link":"https://promotion.aliyun.com/ntms/act/sqlservergaokeyong.html"},{"txt":"快速入门SQL Server","link":"https://help.aliyun.com/document_detail/26141.html"},{"txt":"产品动态","link":"https://www.aliyun.com/product/new?source_type=out_sousuo_feature_0716"}],"countinfo":{"search":{"length_pc":0,"length":0},"card":{"length_pc":0,"length":0}},"simplifiedDisplay":"newEdition","newCard":[{"link":"https://www.aliyun.com/product/rds/sqlserver","title":"云数据库 RDS SQL Server 版","des":"云数据库SQL Server，具有企业许可授权，权限更为开放，引擎功能更为强大。能完美支持Windows平台的.NET架构，支持复杂SQL查询，性能优秀，并有强大的可视化管理工具，帮助您轻松管理数据。","btn1":"产品详情","link1":"https://www.aliyun.com/product/rds/sqlserver","btn2":"管理控制台","link2":"https://rdsnext.console.aliyun.com/#/rdsList/cn-hangzhou/basic/","link3":"https://www.aliyun.com/core/online-consult?from=OVtXEBmlH8","btn3":"在线咨询","infoGroup":[{"infoName":"最新活动","infoContent":{"firstContentName":"新用户年付低至3折起","firstContentLink":"https://www.aliyun.com/activity/database/bestoffers","lastContentName":"2核4GB 299元/年","lastContentLink":"https://rdsbuy.console.aliyun.com/newCreate/rds/mssql?initData={\"data\":{\"rds_dbtype\":\"\tmssql\",\"rds_dbversion\":\"2022_web\",\"rds_web_type\":\"1\",\"rds_class\":\"mssql.share2.medium.w1\",\"rds_storage\":\"100\",\"rds_nodetype\":\"Basic\",\"duration\":12,\"rds_storagetype\":\"cloud_auto\",\"rds_arch\":\"X86\"}}"}},{"infoName":"快速入门","infoContent":{"firstContentName":"帮助文档","firstContentLink":"https://help.aliyun.com/product/26090.html","lastContentName":"入门指南","lastContentLink":"https://help.aliyun.com/document_detail/53729.htm"}},{"infoName":"产品动态","infoContent":{"firstContentName":"存储能力全方位升级","firstContentLink":"https://www.aliyun.com/activity/database/rds-storage-upgrade","lastContentLink":"https://help.aliyun.com/zh/rds/bi-monthly-product-report-for-apsaradb-rds-march-april-2025-2","lastContentName":"RDS 产品双月报"}},{"infoName":"客户案例","infoContent":{"firstContentName":"RDS 助力巴黎奥运会系统稳定运行","firstContentLink":"https://help.aliyun.com/zh/rds/apsaradb-rds-for-sql-server/apsaradb-rds-helps-ensure-the-stability-of-the-system-of-the-paris-olympic-games","lastContentName":"","lastContentLink":""}}],"icon":"","ifIcon":"img","iconImg":"https://img.alicdn.com/tfs/TB1FIpvn3gP7K4jSZFqXXamhVXa-200-200.png","contentLink":"https://www.aliyun.com/product/rds/sqlserver"}]}}

云数据库 RDS SQL Server 版

云数据库SQL Server，具有企业许可授权，权限更为开放，引擎功能更为强大。能完美支持Windows平台的.NET架构，支持复杂SQL查询，性能优秀，并有强大的可视化管理工具，帮助您轻松管理数据。

产品详情

管理控制台

在线咨询