String sql="select * from note where 1=1";
if(name != null){
 sql+=" and name='"+name+"'";
}
if(school != null){
 sql+=" and school='"+school+"'";
}

------解决方案--------------------
探讨


引用:
最简单的办法，拼串

Java code

String sql="select * from note where 1=1";
if(name != null){
sql+=" and name='"+name+"'";
}
if(school != null){
sql+=" and school='"+school+"'";
……


------解决方案--------------------

给你看我的。，

Java code

public List<Employee> specificInquiresr(String ename, String gender,
            String age, String salary, String deptno) throws SQLException {
        Connection conn  = DBUtil.getConnection();
        List<Employee> employees =  new ArrayList<Employee>();
        StringBuffer sql = new StringBuffer();
        sql.append("select * from employee_w where 1=1");
        //String ename1 = ename.trim();
        if(ename.trim()!=""){
            sql.append(" and ename like '%" + ename +"%'");
        }
        
        if(gender.equals("0")){
            sql.append("");
        }else if(gender.equals("1")){
            sql.append(" and gender='男'");
        }else if(gender.equals("2")){
            sql.append(" and gender='女'");
        }
        
        if(age!=""){
            sql.append(" and age= " + age);
        }
        
        if(salary.equals("0")){
            sql.append(" " );
        }else if(salary.equals("1")){
            sql.append(" and salary<3000" );
        }else if(salary.equals("2")){
            sql.append(" and salary between 3000 and 5000" );
        }else if(salary.equals("3")){
            sql.append(" and salary between 5000 and 7000" );
        }else if(salary.equals("4")){
            sql.append(" and salary between 7000 and 9000" );
        }else if(salary.equals("5")){
            sql.append(" and salary>9000" );
        }
        
        if(deptno.equals("0")){
            sql.append(" ");
        }else if(deptno.equals("1")){
            sql.append(" and deptno='1001'");
        }else if(deptno.equals("2")){
            sql.append(" and deptno='1002'");
        }else if(deptno.equals("3")){
            sql.append(" and deptno='1003'");
        }else if(deptno.equals("4")){
            sql.append(" and deptno='1004'");
        }

        String sql1 = sql.toString();
        PreparedStatement ps = conn.prepareStatement(sql1);
        System.out.println(sql1);
        ResultSet rs = ps.executeQuery();
        while(rs.next()){
            Employee e = new Employee();
            e.setId(rs.getLong("id"));
            e.setEname(rs.getString("ename"));
            e.setGender(rs.getString("gender"));
            e.setAge(rs.getInt("age"));
            e.setSalary(rs.getDouble("salary"));
            e.setDeptno(rs.getLong("deptno"));
            employees.add(e);
        }