如何选择id为';It’’s只比空白高一个


how to select the rows with id's just one above gaps

我有一个包含列idname的表。我的重点是id的订单。事实上,我想选择行,当数字的id顺序中断时。看看我的例子:

// mytable
+----+-----------+
| id |    name   |
+----+-----------+
| 1  |   ali     |
| 2  |   jack    |
| 3  |   peter   |
| 5  |   steve   |
| 6  |   lenord  |
| 7  |   jack    |
| 9  |   fered   |
+----+-----------+

现在我想要select where id=5select where id=9。因为CCD_ 7和CCD_。

编辑:我想要这个输出:

// mytable
+----+-----------+
| id |    name   |
+----+-----------+
| 5  |   steve   |
| 9  |   fered   |
+----+-----------+

我可以那样做吗?

事实上,您想要id仅在缺少的id之上的记录;因此,您需要搜索具有id的记录,以使id-1不存在(对于最低id,情况总是如此,因此我们必须明确排除id=1

SELECT *
FROM the_table tt
WHERE id > 1
AND NOT EXISTS (
   SELECT *
   FROM the_table nx
   WHERE nx.id = tt.id -1
   );

尝试使用特定ID进行查找。http://php.net/manual/en/mysqli-result.data-seek.php

<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s'n", mysqli_connect_error());
    exit();
}
$query = "SELECT id, name FROM table";
if ($result = $mysqli->query($query)) {
    /* seek to row no. 4 */
    $result->data_seek(3);
    /* fetch row */
    $row = $result->fetch_row();
    printf ("ID: %s  Name: %s'n", $row[0], $row[1]);
    /* seek to row no. 7 */
    $result->data_seek(6);
    /* fetch row */
    $row = $result->fetch_row();
    printf ("ID: %s  Name: %s'n", $row[0], $row[1]);
    /* free result set*/
    $result->close();
}
/* close connection */
$mysqli->close();
?>

这应该返回:

ID: 5 Name: steve
ID: 9 Name: fered
SELECT x.*
  FROM my_table x 
  LEFT 
  JOIN my_table y 
    ON y.id = x.id - 1 
 WHERE y.id IS NULL 
   AND x.id > 1;
+----+-------+
| id | name  |
+----+-------+
|  5 | steve | 
|  9 | fered | 
+----+-------+