分类：mysql不等于null

2020
10-10

详解mysql不等于null和等于null的写法

1.表结构 2.表数据 3.查询teacher_name字段不能等于空并且也不能等于空字符SELECT*FROMsys_teacherWHEREteacher_nameISNOTNULLANDteacher_name<>''查询结果：4.查询teacher_name字段等于null或等于空字符SELECT*FROMsys_teacherWHEREteacher_name=''ORteacher_nameISNULL查询结果：到此这篇关于详解mysql不等于null和等于null的写法的文章就介绍到这了,更多相关mysql不等于null和等于null内容请搜... 继续阅读 >