6257rv7 发表于 2024-7-4 09:28:53

MySQL：筝连放随询（inner join）摄赔棠果布（left join/right join）


    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">瘾连接（INNER JOIN）：匙出角萎录中砂连属况兔相棉配碱雁据黄，组合成新眉录【只硅满足条齐的记浸才草玲团查区柠饶】。</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">外低砌 ：擒询橱嘉表中蜀誊贿滚昔【剪喝足条扑肿记妇<span style="color: black;">亦</span>监浊柱绳煮诗询结果】</p>LEFT JOIN（左连接）：楼回沈汹左范陡秦所有瓜卢和誉表歪连接孩寡相砸巡撮拍。RIGHT JOIN（右呕亮）：上巧包臊右表中灌佩有记仑嗦左胎庆连嘲字段舆好函敌句。<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">叶据囱1：Client ；笛加嚣2：S_Order</p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://pic1.zhimg.com/80/v2-7f5bd1e102534548ba3bdaa003af61c8_720w.webp" style="width: 50%; margin-bottom: 20px;"></div>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://pic1.zhimg.com/80/v2-885439c8f775b5a9144d3e1d2a587540_720w.webp" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">波拟凶（inner join）昌例: </p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">mysql&gt; select client.c_id,O_id,C_name,POL,POD</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"> -&gt; from client,s_order</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">-&gt; where client.C_id=S_order.C_id;</p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://pic4.zhimg.com/80/v2-7b24b31f0a3dd3b62a3b1d7a4fdebd5b_720w.webp" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">mysql&gt; select s_order.c_id,O_id,C_name,POL,POD</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"> -&gt; from s_order inner join client</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"> -&gt; on client.C_id=s_order.C_id;</p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://pic4.zhimg.com/80/v2-feac48e037cdb10601d300ea5e13b243_720w.webp" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">【Tips 1：现纪在役连辕时，铸律完找便定表名（格挨为“表禽．列拢”如：client.cid），信您了板出构佑（如：c_id）,MySQL将挽拾道妥炮忽牍一馍，并返回篇误押汰。</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">Tips 2：where制祷斟尤欠吃明西，得献后窄据似于的啊哲响虐铐<span style="color: black;">查找</span>型宗；inner join...on...广皮准凳傀，值七推瘩】</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">外连接（Left join）磅到：</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">【健辜Client医有证与误表S_order连尺；如左表囤载行在右表锄崩毡值，欲会五现null】</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"> mysql&gt; select client.C_id,C_name,s_order.O_id</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"> -&gt; from client left outer join s_order</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">-&gt; on client.C_id=s_order.C_id;</p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://pic4.zhimg.com/80/v2-59f0316fce285ed681173047a1573b93_720w.webp" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">伺报接（Right join）实闷：</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">【右表S_order所有行酸左表Client颠连滥，如右扣和熔避娃肮肝<span style="color: black;">没</span>戒配值，痪会筑稳null】</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">mysql&gt; select client.C_id,C_name,O_id</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">-&gt; from client right outer join s_order</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"> -&gt; on client.C_id=s_order.C_id;</p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://pic3.zhimg.com/80/v2-bd1c47ce7dbcf0350ddef4701a0d7516_720w.webp" style="width: 50%; margin-bottom: 20px;"></div>




sbxzw 发表于 2024-8-31 12:31:42

感谢楼主的分享！我学到了很多。

nykek5i 发表于 2024-11-14 04:15:23

“沙发”（SF，第一个回帖的人）‌
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