Question

我有这个问题：

DELETE FROM c_email WHERE code = '67890' AND user_id = '2';
SELECT ROW_COUNT() AS row_1;

我想获得一个名为row_1的字段，删除行数，但似乎无效......

Answer 1

您可以使用不已删除的$mysqli->affected_rows;，如this document

所示

返回值：大于零的整数表示受影响或检索的行数。零表示没有为UPDATE语句更新记录，没有与查询中的WHERE子句匹配的行或者尚未执行任何查询。 -1表示查询返回错误。

来自同一website的一个小例子。

<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* Insert rows */
$mysqli->query("CREATE TABLE Language SELECT * from CountryLanguage");
printf("Affected rows (INSERT): %d\n", $mysqli->affected_rows);

$mysqli->query("ALTER TABLE Language ADD Status int default 0");

/* update rows */
$mysqli->query("UPDATE Language SET Status=1 WHERE Percentage > 50");
printf("Affected rows (UPDATE): %d\n", $mysqli->affected_rows);

/* delete rows */
$mysqli->query("DELETE FROM Language WHERE Percentage < 50");
printf("Affected rows (DELETE): %d\n", $mysqli->affected_rows);

/* select all rows */
$result = $mysqli->query("SELECT CountryCode FROM Language");
printf("Affected rows (SELECT): %d\n", $mysqli->affected_rows);

$result->close();

/* Delete table Language */
$mysqli->query("DROP TABLE Language");

/* close connection */
$mysqli->close();
?>

Answer 2

这是使用PDO。

假设您可以进行一些研究，请设置PDO连接并确保指定此选项：

$db = new PDO ($dsn,$user,$pass,array (
  PDO::ATTR_EMULATE_PREPARES=>TRUE,
));

然后，准备并执行你的陈述。 我不知道任何实际选择已删除行的mysql命令。你必须去rowCount()

$stmt = $db->prepare("DELETE FROM c_email WHERE code = '67890' AND user_id = '2'");
$stmt->execute();
$count = $stmt->rowCount();

但你想在同一个电话中选择第二个查询，所以我们会通过正常选择现有行来做到这一点

$stmt = $db->prepare(
 'UPDATE c_email SET code=1376 WHERE user_id=3;
  SELECT user_id FROM c_email WHERE code=1376;'
);
$stmt->execute(); // this executes both statements, and sets some internal pointer towards the first.
$stmt->nextRowset(); // it's the next one that interests us
$row = $stmt->fetch(PDO::FETCH_ASSOC); // let's get the value
echo $row['user_id'];

Answer 3

开始交易;
SELECT @before：=（SELECT count（）FROM c_email）;
从c_email删除WHERE代码=＆＃39; 67890＆＃39; AND user_id =＆＃39; 2＆＃39;;
SELECT @after：=（SELECT count（）FROM c_email）;
COMMIT;
在AS DELETED之后选择@ before- @;

MySQL ROW_COUNT（）不起作用

3 个答案: