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 * FROM sys_teacher WHERE teacher_name IS NOT NULL AND teacher_name <>'' 查询结果： 4.查询teacher_name字段等于null或等于空字符 SELECT * FROM sys_teacher WHERE teacher_name = '' OR teacher_name IS NULL 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