b1gc8v 发表于 2024-8-4 12:04:00

MySQL中内连接，外连接等的区别


    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">下图展示了&nbsp;</span>LEFT JOIN<span style="color: black;">、RIGHT JOIN、INNER JOIN、OUTER JOIN <span style="color: black;">关联</span>的 7 种用法。</span></p><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtMNn6yE8DYGG45EY78eWlibDzpJOoZnZQpMsTLNgM23wLaJyGjevxB2wg/640?wx_fmt=png&amp;wxfrom=5&amp;tp=webp&amp;wx_lazy=1&amp;wx_co=1" style="width: 50%; margin-bottom: 20px;">
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">详细</span>分解如下：</p>
    <h3 style="color: black; text-align: left; margin-bottom: 10px;"><span style="color: black;"><span style="color: black;">1.INNER JOIN（</span>内连接<span style="color: black;">）</span></span></h3><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtMkA9JlZyhbpGSlagkUgw7paWZnOcrXFC5Gw0XF9QPOKdjRg7lbia99xQ/640?wx_fmt=png&amp;wxfrom=5&amp;wx_lazy=1&amp;wx_co=1&amp;tp=webp" style="width: 50%; margin-bottom: 20px;"><span style="color: black;"><span style="color: black;">SELECT</span> &lt;select_list&gt; </span><span style="color: black;"><span style="color: black;">FROM</span> Table_A A</span><span style="color: black;"><span style="color: black;">INNER</span> <span style="color: black;">JOIN</span> Table_B B</span><span style="color: black;"><span style="color: black;">ON</span> A.Key = B.Key</span>
    <h3 style="color: black; text-align: left; margin-bottom: 10px;">2.LEFT JOIN（左连接）</h3><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtMM1cUQq15ZuLe6Osz3nHJ9aOhvWAia6517ojpb8iaZcKLJWHS4kGYJsog/640?wx_fmt=png&amp;wxfrom=5&amp;wx_lazy=1&amp;wx_co=1&amp;tp=webp" style="width: 50%; margin-bottom: 20px;"><span style="color: black;"><span style="color: black;">SELECT</span> &lt;select_list&gt;</span><span style="color: black;"><span style="color: black;">FROM</span> Table_A A</span><span style="color: black;"><span style="color: black;">LEFT</span> <span style="color: black;">JOIN</span> Table_B B</span><span style="color: black;"><span style="color: black;">ON</span> A.Key = B.Key</span>
    <h3 style="color: black; text-align: left; margin-bottom: 10px;">3.RIGHT JOIN（右连接）</h3><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtMOtVjR3jKXjUPiasmic9qI1fTibSpkiaQmlOSqBfugicTibvzaVFvW10YNRPg/640?wx_fmt=png&amp;wxfrom=5&amp;wx_lazy=1&amp;wx_co=1&amp;tp=webp" style="width: 50%; margin-bottom: 20px;"><span style="color: black;"><span style="color: black;">SELECT</span> &lt;select_list&gt;</span><span style="color: black;"><span style="color: black;">FROM</span> Table_A A</span><span style="color: black;"><span style="color: black;">RIGHT</span> <span style="color: black;">JOIN</span> Table_B B</span><span style="color: black;"><span style="color: black;">ON</span>A.Key = B.Key</span>
    <h3 style="color: black; text-align: left; margin-bottom: 10px;"><span style="color: black;"><span style="color: black;">4.OUTER JOIN（</span>外连接<span style="color: black;">）</span></span></h3><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtMwDkgU17oKCs5bco0o5LPvFCZj0QoxxRBrd1vm5mvGxPLhkKTY4Iw6w/640?wx_fmt=png&amp;wxfrom=5&amp;wx_lazy=1&amp;wx_co=1&amp;tp=webp" style="width: 50%; margin-bottom: 20px;"><span style="color: black;"><span style="color: black;">SELECT</span> &lt;select_list&gt;</span><span style="color: black;"><span style="color: black;">FROM</span> Table_A A</span><span style="color: black;"><span style="color: black;">FULL</span> <span style="color: black;">OUTER</span> <span style="color: black;">JOIN</span> Table_B B</span><span style="color: black;"><span style="color: black;">ON</span> A.Key = B.Key</span>
    <h3 style="color: black; text-align: left; margin-bottom: 10px;">5.LEFT JOIN EXCLUDING INNER JOIN（左连接-内连接）</h3><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtMst9lBmkibqCX9aiaM4EQd1n52Xx7A1H4y1GcLqqgrdU59RfTqUplOwMw/640?wx_fmt=png&amp;wxfrom=5&amp;wx_lazy=1&amp;wx_co=1&amp;tp=webp" style="width: 50%; margin-bottom: 20px;"><span style="color: black;"><span style="color: black;">SELECT</span>&lt;select_list&gt;</span><span style="color: black;"><span style="color: black;">FROM</span> Table_A A</span><span style="color: black;"><span style="color: black;">LEFT</span> <span style="color: black;">JOIN</span> Table_B B</span><span style="color: black;"><span style="color: black;">ON</span> A.Key = B.Key</span><span style="color: black;"><span style="color: black;">WHERE</span> B.Key <span style="color: black;">IS</span> <span style="color: black;">NULL</span></span>
    <h3 style="color: black; text-align: left; margin-bottom: 10px;">6.RIGHT JOIN EXCLUDING INNER JOIN（右连接-内连接）</h3><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtM9OEkyCu7lAIzaAH7BubN2EqPI0KQgGgF9aZr88zWOrcOb2oKy8EN7A/640?wx_fmt=png&amp;wxfrom=5&amp;wx_lazy=1&amp;wx_co=1&amp;tp=webp" style="width: 50%; margin-bottom: 20px;"><span style="color: black;"><span style="color: black;">SELECT</span> &lt;select_list&gt;</span><span style="color: black;"><span style="color: black;">FROM</span> Table_A A</span><span style="color: black;"><span style="color: black;">RIGHT</span> <span style="color: black;">JOIN</span>Table_B B</span><span style="color: black;"><span style="color: black;">ON</span> A.Key = B.Key</span><span style="color: black;"><span style="color: black;">WHERE</span> A.Key <span style="color: black;">IS</span> <span style="color: black;">NULL</span></span>
    <h3 style="color: black; text-align: left; margin-bottom: 10px;">7.OUTER JOIN EXCLUDING INNER JOIN（外连接-内连接）</h3><img src="https://mmbiz.qpic.cn/sz_mmbiz_png/KN0Z2XZibPda0uWMpNhAEaCHFLMuQCVtMjicz3dvrpoFFhWNujr3zDJfJtRjGkB3Kx1uQqArKN8dm57onJXVj3wQ/640?wx_fmt=png&amp;wxfrom=5&amp;wx_lazy=1&amp;wx_co=1&amp;tp=webp" style="width: 50%; margin-bottom: 20px;"><span style="color: black;"><span style="color: black;">SELECT</span> &lt;select_list&gt;</span><span style="color: black;"><span style="color: black;">FROM</span> Table_A A</span><span style="color: black;"><span style="color: black;">FULL</span> <span style="color: black;">OUTER</span> <span style="color: black;">JOIN</span> Table_B B</span><span style="color: black;"><span style="color: black;">ON</span>A.Key = B.Key</span><span style="color: black;"><span style="color: black;">WHERE</span> A.Key <span style="color: black;">IS</span> <span style="color: black;">NULL</span> <span style="color: black;">OR</span> B.Key <span style="color: black;">IS</span> <span style="color: black;">NULL</span></span>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">源自</span>：www.codeproject.com/Articles/33052</p>
    <h2 style="color: black; text-align: left; margin-bottom: 10px;"><span style="color: black;"><span style="color: black;">更加多</span><span style="color: black;">优秀</span><span style="color: black;">文案</span></span></h2>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">1、</span><span style="color: black;">微服务架构下网关的技术选型</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">2、</span></a><a style="color: black;"><span style="color: black;">吊打面试官，最<span style="color: black;">平常</span>的 SpringCloud 微服务面试题</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">3、</span><span style="color: black;">设计一个容错的微服务架构</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">4、<span style="color: black;">为何</span>微服务<span style="color: black;">必定</span>要有网关？</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">5、</span><span style="color: black;">主</span></a>流微服务全链路监控系统之战</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">6、</span><span style="color: black;">全面解析微服务系统监控分层，啃透服务治理核心！</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">7、</span><span style="color: black;">设计一个容错的微服务架构</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;">8、深挖，一文搞懂 Sentinel 限流熔断！</a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">9、</span><span style="color: black;">从零搭建 SpringCloud Alibaba 鉴权中心服务（<span style="color: black;">仔细</span>教程）</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;"><span style="color: black;">十、</span></span><span style="color: black;">什么是脚手架？<span style="color: black;">为何</span><span style="color: black;">必须</span>脚手架？常用的脚手架有<span style="color: black;">那些</span>？</span></a></p>
    <h1 style="color: black; text-align: left; margin-bottom: 10px;"><a style="color: black;">11、<span style="color: black;">行业</span>驱</a>动设计（DDD）的几种典型架构介绍</h1>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">12、</span><span style="color: black;">微服务网关鉴权：gateway<span style="color: black;">运用</span>、网关限流<span style="color: black;">运用</span>、用户<span style="color: black;">秘码</span>加密、JWT鉴权</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">13、</span><span style="color: black;">Spring Cloud Sleuth 全链路日志跟踪<span style="color: black;">处理</span><span style="color: black;">方法</span>（<span style="color: black;">剧烈</span><span style="color: black;">举荐</span>）</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><a style="color: black;"><span style="color: black;">14、</span><span style="color: black;">SpringCloud整合Alibaba Seata实现分布式事务</span></a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">如<span style="color: black;">爱好</span>本文，请点击右上角，把<span style="color: black;">文案</span>分享到<span style="color: black;">伴侣</span>圈</p>

    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">因公众号更改推送规则，请点“在看”并加“星标”<span style="color: black;"><span style="color: black;">第1</span>时间获取精彩技术分享</span></span></strong></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">·END·</strong></p>




7wu1wm0 发表于 2024-10-20 06:44:03

交流如星光璀璨，点亮思想夜空。

qzmjef 发表于 2024-11-2 13:26:58

你的见解独到，让我受益匪浅，非常感谢。

1fy07h 发表于 2024-11-14 17:40:23

这夸赞甜到心里，让我感觉温暖无比。
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