小编Mah*_*ine的帖子

我有两个名字tab1和表tab2.

TAB1是P&rimary key is price并且price is foreign key in tab2,它是on delete set null.

当我primary key从tab2中存在的tab1中删除一个相应的外键

设置为NULL.

现在我想从tab2中删除其外键为null的行.

我写这个查询,但它不起作用.

delete from tab2 where price = null.

请帮我解决一下.

我有这个代码:

 Date start = new Date(Integer.parseInt(jTextField4.getText()), Integer.parseInt(jTextField16.getText()), Integer.parseInt(jTextField17.getText()));  
        Date end = new Date(Integer.parseInt(jTextField5.getText()), Integer.parseInt(jTextField18.getText()), Integer.parseInt(jTextField19.getText()));
        statement = connection.createStatement();
        preparedStatement1 = connection.prepareStatement("insert into sportmangg(customer_code,"
             + "sportman_code, start, finish, salary,amount,box salary,private salary, food salary, "
             + "other salary, bime salary, number) "
             + "values (? ,?, ? , ?, ?, ?, ?, ?, ?, ?, ?, ?");
      preparedStatement1.setString(1,jTextField15.getText());
     preparedStatement1.setString(2, jTextField1.getText());
     preparedStatement1.setDate(3, start);
     preparedStatement1.setDate(4, end);
     preparedStatement1.setInt(5, Integer.parseInt(jTextField6.getText()) );
     preparedStatement1.setInt(6,Integer.parseInt(jTextField14.getText()) );
     preparedStatement1.setInt(7, Integer.parseInt(jTextField7.getText()));
     preparedStatement1.setInt(8, Integer.parseInt(jTextField8.getText()));
     preparedStatement1.setInt(9, Integer.parseInt(jTextField9.getText()));
     preparedStatement1.setInt(10, Integer.parseInt(jTextField11.getText()));
     preparedStatement1.setInt(11, Integer.parseInt(jTextField10.getText()));
     preparedStatement1.setInt(12, Integer.parseInt(jTextField20.getText()));
     preparedStatement1.executeUpdate(); …

我想知道如何在mysql db中存储图像并在需要时检索它.

我想用java和netbeans使用图像.

我有一个名称1.php中包含函数的页面.现在我想2.php在PHP 2中调用该函数.我写了func();这个函数1.php.

但它有这个错误:

Fatal error: Call to undefined function func() in C:\xampp\htdocs\me\2.php on line 2

我怎样才能做到这一点？

我需要转换integer到byte并在文件中写字节,但是当我转换大于128的数字节转换为负数.我需要使用unsigned char,但我不知道如何.在c ++我们写,unsigned但它在java中是怎么回事？

select * from temp where ssn not in (select distinct ssn from temp inner join
tamp where ssn,code_dars not in(select ssn,code_dars from temp));

错误1064(42000):您的SQL语法有错误; 检查与您的MySQL服务器版本对应的手册,以便在第3行的'code_dars not(select ssn,code_dars from temp)'附近使用正确的语法

<script type="text/javascript">
           function mehdi()
           {
               alert('salam');
              <?php 
               echo'hi';
               ?>

             }

</script>
this is html:
      <input type="button" name ="submit" value="submit" onclick= "mehdi()">

如果ehco将在此代码中执行？如果没有,我怎么运行它？