MySql 创建多字段主键

1.如果已有主键要先清除现有主键

ALTER TABLE yourtable
DROP PRIMARY KEY;
PS：如果你的主键是自增的，要先去除自增特性 才能去除主键

2. 创建复合主键

ALTER TABLE yourtable
ADD PRIMARY KEY (employeeid, recordmonth, recordyear);

标签：自增,yourtable,PRIMARY,主键,多字段,MySql,TABLE,ALTER
来源： https://www.cnblogs.com/wkk2020/p/15715134.html