得到某个表的某个字段的最大值（Oracle与Mysql的区别）

（1）Oracle中

public String getMaxIdInfo(String table, String columname) {

String sql = "select max(to_number("+columname+")) from "+table;

String num = "";

con = dbc.getConnection();

try {

pst = con.prepareStatement(sql);

//pst.setString(1, columname);

//pst.setString(2, table);

rs = pst.executeQuery();

if (rs.next()) {

num = (rs.getInt(1)+1)+"";

}

} catch (Exception e) {

Menulogger.debug("获取最大ID信息失败！"+e);

e.printStackTrace();

// TODO: handle exception

}finally{

dbc.closeQuery(rs, pst, con);

}

return num;

}

（2）MySql中

public String getMaxIdInfo(String table, String columname) {

String sql = "select max("+columname+"+0) from "+table;

String num = "";

con = dbc.getConnection();

try {

pst = con.prepareStatement(sql);

//pst.setString(1, columname);

//pst.setString(2, table);

rs = pst.executeQuery();

if (rs.next()) {

num = (rs.getInt(1)+1)+"";

}

} catch (Exception e) {

Menulogger.debug("获取最大ID信息失败！"+e);

e.printStackTrace();

// TODO: handle exception

}finally{

dbc.closeQuery(rs, pst, con);

}

return num;

}