2023-06-10

1.https://blog.51cto.com/yueshushu/5841057
2.https://blog.51cto.com/u_16099229/6357421 mysql if多个条件 mysql if函数 多条件
3.https://blog.csdn.net/weixin_32080327/article/details/113441135 mysql 特殊函数_MySQL特殊一些函数
4.https://blog.csdn.net/weixin_39904809/article/details/113441140 mysql 特殊函数
4.mysql 函数 https://blog.csdn.net/weixin_45441862/article/details/121414706?utm_medium=distribute.pc_relevant.none-task-blog-2~default~baidujs_baidulandingword~default-1-121414706-blog-113441140.235^v38^pc_relevant_anti_vip&spm=1001.2101.3001.4242.2&utm_relevant_index=4