Time difference in execution of the same query between PHP and PHPMYADMIN

Question

I am trying to improve the performance of my pages to improve the user experience, but, I am not able to identify the problem.

According to Google, it is recommended that the pages respond in less than 0.4 seconds, however, only the connection to the database, this taking 0.41 seconds. Whether by mysql_connect or mysqli_connect

Also, the same query I run to mount a menu, in PHP it takes on average 0.14 but in phpMyAdmin it only takes 0.0009 as shown in execution

Showing records from 0 - 24 (total 35, Query took 0.0009 sec)

I created an empty page, only with connection and query to measure times

http://omenorpreco.com/teste.php

Anyone have any idea how can I decrease the time to make the connection, and, decrease the query time to turn into Phpmyadmin?

UPDATE:

//PHP
    $sql = "select cd_categoria, linha, slug, cd_categoria_site, qtd from ( SELECT cd_categoria, if (menu.cd_categoria_pai=0,menu.nm_categoria,concat((select nm_categoria from tb_st_category where cd_categoria = menu.cd_categoria_pai),';',nm_categoria)) as linha , if (menu.cd_categoria_pai=0,menu.nm_slug,concat((select nm_slug from tb_st_category where cd_categoria = menu.cd_categoria_pai),'/',menu.nm_slug)) as slug , cd_categoria as cd_categoria_site , 0 as qtd FROM tb_st_category menu where cd_categoria_pai = 0 ) as a order by linha";
    $pagespeed = microtime_float();
    $query = $mysqli->query($sql);
    echo "Query Time:".number_format(microtime_float()-$pagespeed, 2, ',', '')."<br>";

My SQL server is Windows (WAMP)

Ja includes the Skip-name-resolve variable in the WAMP configuration file

Connection is remote, done via IP, not the server name

Answer 1

This performance test is PHP and not query, so it will give different results always, to debug a query you can use the set profiling=1;

mysql> set profiling=1;
mysql> EXPLAIN SELECT ...
mysql> SELECT ...
mysql> ALTER ...
mysql> show profiles;
+----------+------------+-------------------------
| Query_ID | Duration   | Query
+----------+------------+-------------------------
|        1 | 0.00036500 | EXPLAIN SELECT sbvi.id a
|        2 | 0.00432700 | SELECT sbvi.id as sbvi_i
|        3 | 2.83206100 | alter table sbvi drop in
|        4 | 0.00047500 | explain SELECT sbvi.id a
|        5 | 0.00367100 | SELECT sbvi.id as sbvi_i
+----------+------------+-------------------------

Documentation: http://dev.mysql.com/doc/refman/5.7/en/show-profile.html