PreparedStatementps=conn.prepareStatement("select*fromtodaywhereusername=?andyear2=?andmonth2=?andday2=?");ps.setString(1,username);ps.setString(2,year2);ps.setString(3,month2);ps.setString(4,day2);ResultSetrs=ps.executeQuery();这个

Question

PreparedStatement ps = conn
.prepareStatement("select * from today where username=?and year2=?and month2=?and day2=?");
ps.setString(1,username);
ps.setString(2,year2);
ps.setString(3,month2);
ps.setString(4,day2);
ResultSet rs = ps.executeQuery();
这个哪错了吗?

Answer 1

String sql = "SELECT userid,name FROM tuser WHERE userid=?AND password=?" ;
pstmt = conn.prepareStatement(sql) ;
pstmt.setString(1,userid) ; // 这里设置了第一个?的值
pstmt.setString(2,password) ; // 这里设置了第二个?的值
等你“setString”完所有的?后,你的sql就构造好了.