gpt4 book ai didi

SQL JOIN 和不同类型的 JOIN

转载 作者:行者123 更新时间:2023-11-30 21:55:39 32 4
gpt4 key购买 nike

什么是 SQL JOIN,有哪些不同的类型?

最佳答案

插图来自 W3schools :


INNER JOIN - Only records which match the condition in both tables


LEFT JOIN - All records from table 1 in conjunction with records which match the condition in table 2


RIGHT JOIN - All records from table 2 in conjunction with records from table 1 which match the condition


FULL OUTER JOIN - Combination of both Left and Right Outer joins matching ON clause but preserving both tables


关于SQL JOIN 和不同类型的 JOIN,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45290536/

32 4 0
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com