MySQL -- How to do this better? - php

Question

$activeQuery = mysql_query("SELECT count(`status`) AS `active` FROM `assignments` WHERE `user` = $user_id AND `status` = 0");
$active = mysql_fetch_assoc($activeQuery);
$failedQuery = mysql_query("SELECT count(`status`) AS `failed` FROM `assignments` WHERE `user` = $user_id AND `status` = 1");
$failed = mysql_fetch_assoc($failedQuery);
$completedQuery = mysql_query("SELECT count(`status`) AS `completed` FROM `assignments` WHERE `user` = $user_id AND `status` = 2");
$completed = mysql_fetch_assoc($completedQuery);
There has to be a better way to do that, right? I don't know how much I need to elaborate as you can see what I'm trying to do, but is there any way to do all of that in one query? I need to be able to output the active, failed, and completed assignments, preferably in one query.

Answer 1

You can try something like this query
SELECT Status , COUNT(*) StatusCount
FROM assignments
WHERE Status IN (0, 1, 2)
AND User = $user_id
GROUP BY Status

Answer 2

Try this
$activeQuery = SELECT status, count(status) as "status count" FROM `assignments` WHERE `user` = $user_id GROUP BY `status`
edit: added group by

Answer 3

Instead of doing them individually you could use the following single SQL statement
SELECT count(*), `status`
FROM `assignments`
WHERE `user` = $user_id
AND `status` in (0,1,2)
GROUP BY `status`
ORDER BY `status`
The loop around the result set to extract the results.

Answer 4

SELECT
(SELECT COUNT(*) FROM `assignments` WHERE `user` = $user_id AND `status` = 0) AS active,
(SELECT COUNT(*) FROM `assignments` WHERE `user` = $user_id AND `status` = 1) AS failed,
(SELECT COUNT(*) FROM `assignments` WHERE `user` = $user_id AND `status` = 2) AS completed,
FROM `assignments`
GROUP BY active, failed, completed
Haven't checked the markup, but this is near or near enough.

Answer 5

Use the GROUP BY to get it in one query, but on separate rows.
$query = mysql_query("SELECT `status`, count(*) AS `num` FROM `assignments` WHERE `user` = $user_id AND `status` in (0,1,2) GROUP BY `status` ORDER BY `status` ASC");
$active_count = 0;
$failed_count = 0;
$completed_count = 0;
while ($array = mysql_fetch_assoc($query))
{
if ($array['status'] == 0)
$active_count = $array['num'];
else if ($array['status'] == 1)
$failed_count = $array['num'];
else if ($array['status'] == 2)
$completed_count = $array['num'];
}

Answer 6

When I have the option, I'm in the habit of using prepared statement(s) to help protect against sql-injection protection and for efficiency (requires using mysqli).
But if this is not an option, then
SELECT
CASE `status`
WHEN 0 THEN `active`
WHEN 1 THEN `failed`
WHEN 2 THEN `completed`
ELSE `unknown`
END
AS `statuslabel`,
COUNT(status)
AS `statuscount`
FROM `assignments`
WHERE `user` = $escaped_user_id
GROUP BY `statuslabel`
ORDER BY `statuslabel`
Note the use of the $escaped_user_id, which would be created beforehand:
$escaped_user_id = mysql_real_escape_string($user_id);