相当于mysql_num_rows或mssql_num_rows的PDO [英] PDO equivalent of mysql_num_rows or mssql_num_rows

问题描述

我知道以前曾问过这个问题，但似乎解决方案是针对所提出问题的.

I know this question has been asked before but it seems like the solutions have been specific to the problem presented.

我有一个包含数百个使用mssql_num_rows的实例的代码库.

I have a codebase with hundreds of instances where mssql_num_rows is used.

代码示例:

$db->execute($sql);

if ($db->getRowsAffected() > 0) {
    $total = $db->fetch();

在db类中:

$this->rowsaffected = mssql_num_rows($this->query_result);

• 我无法创建通用的SELECT count(*) FROM table查询，因为我有太多特定的select语句.
• 我可以运行preg_replace删除SELECT and FROM之间的所有内容，然后替换为COUNT(*)并运行第二个查询，但这假定所有查询都以某种方式设置.
• 我可以先fetchAll然后count()结果，但这意味着升级if语句的所有实例.
• I can't create generic SELECT count(*) FROM table queries as I have too many specific select statements.
• I could run a preg_replace to remove everything between SELECT and FROM and then replace with a COUNT(*) and run a second query but this assumes all queries are setup a certain way.
• I could fetchAll first then count() the results but that means upgrading all instances of the if statements.

因此，如果人们将其代码更新为PDO，那么最好替换* _num_rows函数.不是解决特定问题的方法，而是替代* _num_rows功能的方法.如果不可能的话，那么以前怎么可能呢?

So what is the best all around replacement to a *_num_rows function if people are updating their code to PDO. Not something that solves a specific problem, but something that replaces the functionality of *_num_rows. If that's not possible what allowed it to be possible before?

推荐答案

如果要计算行数，可以使用PDO做到这一点:

If you want to count the rows you can do this with PDO:

$sql = 'select * from users';
$data = $conn->query($sql);
$rows = $data->fetchAll();
$num_rows = count($rows);

在PDO中使用SELECT语句时，无法直接对行进行计数.

There is no way to directly count rows when using a SELECT statement with PDO.

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