How to optimize nested query with PHP and MySqli? - php

Question

I have this code, that fetches data from two tables in MySQLi.
It first has to get the title, description, status and project_id from table 1, and then get the name from table 2 using the id from table 1.
Is there a better/faster way to do this? I have about 600 rows in the tables, and it takes about 5 sec to run this query. I will also add that this example is a bit simplified, so please don't comment on the db-structure.
<?php
$results = $connect()->db_connection->query(
'SELECT title, description, status, project_id
FROM table
WHERE created_by ='.$user_id
);
if ($results) {
while ($result = $results->fetch_object()) {
$res = $connect()->db_connection->query(
"SELECT name FROM projects WHERE id = ".$result->project_id
);
if ($res) {
while ($r = $res->fetch_object()) {
echo $r->name;
}
}
echo $result->title;
echo $result->status;
}
}
?>

Answer 1

Use Query:
SELECT title,description,status,project_id
FROM table tb
inner join projects pr on pr.id = tb.project_id
WHERE created_by = $user_id

Answer 2

Try to use JOIN in your query.
You can find examples and description of this command here: http://www.w3schools.com/sql/sql_join.asp
Check out also this infographics:
http://www.codeproject.com/KB/database/Visual_SQL_Joins/Visual_SQL_JOINS_orig.jpg

Answer 3

You can use JOIN on project_id:
$results = $connect()->db_connection->query('SELECT t.title title,t.description,t.status status,t.project_id, p.name name FROM `table` t JOIN projects p ON p.id= t.project_id WHERE t.created_by ='.$user_id);
if($results){
while($result = $results->fetch_object()){
echo $result->name;
echo $result->title;
echo $result->status;
}
}
tables have aliases here - t for table and p for projects.
Also to make it faster, add index to project_id in table table, if you haven't done it yet:
$connect()->db_connection->query('ALTER TABLE `table` ADD INDEX `product_id`');