git 提交代码 Couldnt check the working tree for unmerged files because of an error. bad signature 0x00000000 index file corrupt
报错,无法提交
原因:导入错误项目或者误删除 导致index 文件虽坏 解决办法,找到项目下 .git 下的ind…
问题:mysql版本5.7,使用group by 分组查询遇到
Error : Expression #2 of SELECT list is not in GROUP BY clause
and contains nonaggregated column mysql.course.cname
which is not functionally dependent on columns in GROUP BY clause;
this…