java.sql.SQLException: Field ‘userID‘ doesn‘t have a default value at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2921) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1570) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1665) at com.mysql.jdbc.Connection.execSQL(Connection.java:2972) at com.mysql.jdbc.Connection.execSQL(Connection.java:2902) at com.mysql.jdbc.Statement.executeUpdate(Statement.java:929) at Demo2.demo2.main(demo2.java:30)

这个问题的出现主要是因为数据库的属性userID没有进行声明

String userID = null;

String sql = "insert into user(userID,userName,password) values(‘"+userID+"‘,‘"+userName+"‘,‘"+password+"‘)";

数据库添加数据时出现的问题