MYSQL变量在PHP查询

Question

I am trying to query multiple mysql statement in one query but failed.

$testq ="";
        $testq .= mysql_query("SET @@group_concat_max_len = 5000");
        $testq .= mysql_query("SET @sql = NULL");
        $testq .= mysql_query("SELECT   GROUP_CONCAT(DISTINCT
                    CONCAT(
                      'MAX(IF(property_name = ''',
                      property_name,
                      ''', value, NULL)) AS ',
                      property_name
                    )
                  ) INTO @sql FROM properties");
        $testq .= mysql_query("SET @sql = CONCAT('SELECT item_id, ', @sql, ' FROM properties GROUP BY item_id')");
        $testq .= mysql_query("PREPARE stmt FROM @sql");
        $testq .= mysql_query("EXECUTE stmt"); 
        $da = mysql_query($testq, $dbconnect);          
        while($rt = mysql_fetch_assoc($da){
            //print
             }

Error is: Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in C:\\Users.....on line 24 How can I do this query and print the result in table?

Answer 1

The MySQL extension in PHP does not support multi queries in PHP for security reasons with mysql_query . You should not use MySQL anymore furthermore, use MySQL i .

You should use UNION or something like this to concat the queries. If you just want to make a multi query, you should use mysqli_multi_query within the MySQL i library.

Then the syntax have to be another. The queries have to be submitted as one string in one function like this:

$mysqli->multi_query("SELECT * FROM table; TRUNCATE table; DROP table;");