mysql查询有时不总是失败

Question

I have a simple mysql query in a PHP page. The query is somehow like this-

$q=mysql_query("SELECT * FROM ip_tables");  
echo mysql_num_rows($q);  

The number of rows in ip_tables is simply 5-10 . The problem is this simple query fails sometimes without any reason. For example, sometimes I load the page and find the error message Warning: invalid argument supplied to mysql_num_rows. resource required, boolean given in ... Warning: invalid argument supplied to mysql_num_rows. resource required, boolean given in ... .

But at that moment if I refresh the page, the error does not occur and it shows the correct row number. This problem occurs sometimes not always. Anyone have a solution for this?

Thanks

Answer 1

这将在您的错误日志文件中记录mysql错误：mysql_query（“ SELECT * FROM ip_tables”）或error_log（mysql_error（））;