我的数据库是一个表:USER_ID和NAME,还有ROLE,我想通过USER_ID来查找它的ROLE。
ROLE有三种A,M ,D
然后用java语句判断这个ROLE,如果
ROLE=‘N’ return normal
ROLE=‘m’return manage
ROLE= ‘d’return director
小妹初学java,请问哪位好心人帮我写下过程~在线等待,先谢谢大家了
ROLE有三种A,M ,D
然后用java语句判断这个ROLE,如果
ROLE=‘N’ return normal
ROLE=‘m’return manage
ROLE= ‘d’return director
小妹初学java,请问哪位好心人帮我写下过程~在线等待,先谢谢大家了
select * from 这个表 where user_id = 'xx'
java:
if(role.equals("n"){
return "normal";
}else if (role.equals("m")){
return "manager";
}else{
return "director";
}
Connection conn = DriverManager.getConnection (url,username,password);
Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery ("select * from 表名 where user_id = ...");
if(rset.next())
{
String role = rset.getString("role");
if(role.equals("n")
{
...
}
else if (role.equals("m"))
{
...
}
else
{
...
}}
rset.close();
stmt.close();
conn.close()
select role case
when 'N' then 'normal'
when 'M' then 'manager'
when 'D' then 'director'
from ...
where user_id = 'xxx'
可能写的不对,好久没写sql了大概思路是这样的,欢迎“髙兽”指正,
String sql="select CASE ROLE
WHEN 'N' THEN 'normal'
WHEN 'M' THEN 'manage'
WHEN 'D' THEN 'director'
ELSE NULL END
from table where USER_ID="+USER_ID变量;ResultSet rset = stmt.executeQuery (sql);
{
Connection conn;
Statement stmt;
ResultSet firstres,midres,lastres;
//加载Connector/J驱动
//这一句也可写为:Class.forName("com.mysql.jdbc.Driver");
Class.forName("com.mysql.jdbc.Driver").newInstance();
//建立到MySQL的连接
conn = DriverManager.getConnection("jdbc:mysql://192.168.0.244:3306/XHLYDB","root", "");
//执行SQL语句
stmt = conn.createStatement();
firstres = stmt.executeQuery("select USER_LVL from USER_INFO where USER_ID='aaaa'");
//处理结果集
String owner;
while (firstres.next())
{
String role = firstres.getString("USER_LVL");
if(role.equals("M")){
owner = "director";
}
else if(role.equals("AM")){
midres=stmt.executeQuery("select USER_ID from USER_INFO WHERE USER_LVL='M'");
owner = "manager";
}
else {
lastres=stmt.executeQuery("select USER_ID FROM USER_INFO WHERE USER_LVL='M'");
owner = "salesman";
}
System.out.println(owner);
}
}
catch (Exception ex)
{
System.out.println("Error : " + ex.toString());
}