如何在“SELECT TABLE_NAME FROM information_schema.TABLES”中使mysql“num_rows”工作？

Question

$query_Recordset4 = sprintf("SELECT TABLE_NAME FROM information_schema.TABLES 
 WHERE TABLE_SCHEMA='message' and TABLE_NAME like '1a%nd5'");
 $Recordset4 = mysql_query($query_Recordset4, $messageconnection);
 $totalRows_Recordset4 = mysql_num_rows($Recordset4);

I ran SQL query about SELECT TABLE_NAME FROM information_schema.TABLES WHERE TABLE_SCHEMA='message' and TABLE_NAME like '1a%nd5' in PhpMyAdmin. It revealed "2" total rows.

However, I queried the answer "mysql_num_rows" in php was "0". Doesn't "mysql_num_rows" work in SELECT TABLE_NAME FROM information_schema.TABLES? What is the alternative method?

If a alternative method is below content. $query_Recordset5 = sprintf("SELECT COUNT(*) FROM information_schema.TABLES WHERE TABLE_SCHEMA='message' and TABLE_NAME like '$colname_Recordset6' "); $row_Recordset5 = mysql_fetch_assoc($Recordset5);

The result of "mysql_fetch_assoc" revealed nothing, but it worked in other mysql_query. How can I solve this problem?

Answer 1

Your problem is actually in your call to sprintf, it is trying to process %n as a conversion specification. You need to change the % in that string to %% i.e.

$query_Recordset4 = sprintf("SELECT TABLE_NAME FROM information_schema.TABLES WHERE TABLE_SCHEMA='message' and TABLE_NAME like '1a%%nd5'");

You should also switch from using mysql_ functions to mysqli_ as the mysql functions have been deprecated as of PHP5.5 and removed as of PHP7 due to bugs in the code.