php - PHP count row returns error

Question

i'm using the following to count the number of rows in my table:

$book_count = query("SELECT status FROM scifi_book WHERE read = $uid");
(count($book_count));
echo $book_count;

and i get the following error:

Notice:  Array to string conversion on line 167

(which is the line echo $book_count;)

FIY, the query function is defined and works fine. Never had any issues to insert, select, update and delete.

Am I missing something here?

score 2 · Accepted Answer

尝试这个：

$book_count = query("SELECT status FROM scifi_book WHERE read = $uid");
echo count($book_count);

此外，您需要使用，print_r($book_count)因为您$book_count的不是字符串。

score 2 · Accepted Answer

建议：如果您只使用该查询来获取计数，这可能会更好一些：

$book_count = query("SELECT count(*) FROM scifi_book WHERE read = $uid");

score 1 · Accepted Answer

您的查询函数似乎返回一个数组，而不是一个字符串。而不是echo $follower_count用来print_r($follower_count)查看查询响应中的内容。

score 1 · Accepted Answer

您看到该错误的原因是因为您正在echoingArray这是您的query函数返回的。 echo构造仅适用于字符串，请参阅此处的文档：http ://www.php.net/manual/en/function.echo.php 。

如果您使用过print_r，否则var_dump您将不会看到该错误。所以@AS Roma 和 Nathaniel Granor 建议使用print_r

score 1 · Accepted Answer

$book_count = query("SELECT status FROM scifi_book WHERE read =".$uid);
(count($book_count));
echo $book_count;

5 回答 5