For my mobile App i am using a web service to get the images and all records from the MySQL database, its like Instagram.
But SELECT DISTINCT taking more than 7 - 8 seconds.is there any thing that i can do for reduce the time?
SELECT distinct count(*) as totalrecord ,p.description,p.photo_id ,p.user_id,p.imagepath1 ,p.friends, p.is_report_photo,
p.imagepath2,p.imagepath3,p.imagepath4,p.imagepath5,p.count_comment,p.count_like,p.created as photo_created ,
(select username from users where id = p.user_id) as username ,
(select country from users where id = p.user_id) as country,
(select email from users where id = p.user_id) as email ,
(select image_path from users where id = p.user_id) as image_path ,
(select gender from users where id = p.user_id) as gender,
(select privacy from users where id = p.user_id) as privacy,
(select audio_privacy from users where id = p.user_id) as audio_privacy,
(select video_privacy from users where id = p.user_id) as video_privacy,
(select photo_privacy from users where id = p.user_id) as photo_privacy,
If(pl.user_id && pl.photo_id !='',like_status,0) as islike ,
If(pr.user_id && pr.photo_id !='',1,0) as isreport,
p.user_visibility
from friends as fr
inner join users as u on u.id = (select distinct if (fr.user_id != $user_id,fr.user_id,(fr.to_user_id)) as rd
from friends) && fr.read_status = '1'
inner join photos as p on (p.user_visibility = 'p')
LEFT JOIN photolike as pl ON pl.photo_id = p.photo_id && pl.user_id = $user_id
LEFT JOIN photo_report as pr on pl. photo_id = pr.photo_id && pr.user_id = $user_id
ORDER BY p.photo_id DESC;
Use mysql indexing that will reduce the time
Try using group-by clause instead of distinct.
Related
Table -1 : Comment id, comment,user_id,comment Date
Table -2: Users id, user_name, full_name, password
now i want to get user detaiils records who is last comment
like
query is :
select c.*,
(select user_name
from users
where id = c.user_id
) as user_name,
(select full_name
from users
where id = c.user_id
) as full_name
from comment as c, users as u
group by c.user_id
order by comment_date DESC
SELECT Users.*,
Comment.*
FROM Users
INNER JOIN Comment ON (Comment.user_id = Users.id)
GROUP BY Users.id
ORDER BY Comment.id DESC
that should work
Here is your query
select users.* from users inner join comments on
users.user_id = comments.user_id
order by comments.comment_date desc limit 1
Another way to do this
select * from users where user_id =
(select user_id from comments order by comment_date desc limit 1)
I have one chat table there is reference id of user table use in user_from and user_to.
Now I have to a query for get a chat member list from chat table like facebook caht list.
with whom I have chat and I have to find name of user from user table and unread counter
Please give me solution for this
Thanks
I think your subquery needs to be correlated, which will be slow.
Use JOIN instead.
SELECT
users.id AS userid,
chat_box.id AS msgid,
first_name,
last_name,
profile_pic,
LEFT(message, 50) AS message,
u.unreadcounter
FROM
chat_box
LEFT JOIN
users ON (chat_box.user_from = users.id)
LEFT JOIN
(SELECT
u.id, COUNT(c.id) unreadcounter
FROM
chat_box c
JOIN users u ON (c.user_from = u.id)
WHERE
c.read = 0 && c.user_to = 45
GROUP BY u.id) u ON users.id = u.id
WHERE
(user_from = 45 OR user_to = 45)
&& users.id != 45
GROUP BY users.id
UNION SELECT
users.id AS userid,
chat.id AS msgid,
first_name,
last_name,
profile_pic,
LEFT(message, 50) AS message,
0 AS unreadcounter
FROM
chat_box AS chat
LEFT JOIN
users ON (chat.user_to = users.id)
WHERE
(user_from = 45 OR user_to = 45)
&& users.id != 45
GROUP BY users.id
ORDER BY msgid DESC
I'm trying to make a internal web based message system, with a *amp system, primarily for learning purposes. I don't know if this is a trivial topic, but I'm having difficulties so please bear with me.
The goal is to list all the contacts ordered by the last message sent / received.
Currently without sorting it the SQL looks like this
$query = "SELECT username, user.id as user_id,
(SELECT COUNT(message_read)
FROM message_user
WHERE message_read = 0
AND sent_id = user_id
AND receive_id = {$userId}) as unread
FROM user
WHERE user.id IN
(SELECT contact_id FROM allowed_contact WHERE user_id = {$userId})
;";
The structure of the tables are:
The user table has an id,
That links to the message_user table which has a sent_id and a receive_id,
The message_user has a message_id that corresponds to the message.id,
The message table has a timestamp.
I would like this to be done in SQL but if it comes down to PHP I resign to resort to that.
This works.
SELECT `u`.`id` AS user_id, username,
(SELECT COUNT(message_user.message_read)
FROM message_user
WHERE message_user.message_read = 0
AND sent_id = user_id
AND receive_id = {$userId}) as unread
FROM `user` AS `u`
LEFT JOIN `message_user` AS `mu`
ON
(CASE WHEN `u`.`id` != {$userId}
THEN `u`.`id` = `mu`.`sent_id`
WHEN `mu`.`sent_id` = {$userId} AND `mu`.`receive_id` = {$userId}
THEN `u`.`id` = `mu`.`sent_id`
END)
OR
(CASE WHEN `u`.`id` != {$userId}
THEN `u`.`id` = `mu`.`receive_id`
END)
LEFT JOIN `message` AS `m` ON `m`.`id` = `mu`.`message_id`
WHERE u.id IN
(SELECT contact_id FROM allowed_contact WHERE user_id = {$userId})
GROUP BY u.id
ORDER BY MAX(`m`.`timestamp`) DESC;
This broke down the problem I was having.
#Andreas thanks for time and help.
Use 2 LEFT JOIN with a DISTINCT (untested):
SELECT DISTINCT `u`.`id`
FROM `user` AS `u`
LEFT JOIN `message_user` AS `mu` ON `u`.`id` = `mu`.`sent_id` OR `u`.`id` = `mu`.`receive_id`
LEFT JOIN `message` AS `m` ON `m`.`id` = `mu`.`message_id`
ORDER BY `m`.`timestamp` DESC;
I have an application, very basic description:
Users login -> they post "activities" (like snowboarding)
Users have friends
Users can bind multiple friends to activities
Users can "like" activities created by friends
What I need is a query to check if the user is allowed to "like" an activity by one of their friends. They are only allowed when one of the users friends was bound to the target activity.
users: id, name
usersFriends: id, uid, friendUid
activities: id, description
activitiesUsers: id, activityId, uid
activitiesLikes: id, activityId, uid
I hope someone can help me with this query, and if possible to return true or false. I hope my question is clear and thanks for your time :)
This should produce a list of activities.id for all of the user's friends.
SELECT
activities.id AS canLikeId
FROM
users u
JOIN usersFriends uf ON u.id = uf.uid
JOIN activitiesUsers au ON uf.friendId = au.uid
JOIN activities a ON a.id = au.activityId
Wrapped in an EXISTS, it looks like:
SELECT activities.id FROM activities aCanLike
WHERE EXISTS (
SELECT
a.id AS canLikeId
FROM
users u
JOIN usersFriends uf ON u.id = uf.uid
JOIN activitiesUsers au ON uf.friendId = au.uid
JOIN activities a ON a.id = au.activityId
WHERE a.id = aCanLike.id
)
Or something with an IN() clause that attempts to get everything from activities owned by any of the user's friends.
SELECT
activities.*
FROM activities JOIN activitiesUsers ON activities.id = activitiesUsers.activityId
WHERE activitiesUsers.uid IN (
SELECT friendUid FROM usersFriends WHERE uid = $userid
)
Assuming you know the user's id and activity id at the time of the query, you could do something like:
SELECT COUNT(*) FROM activitiesUsers WHERE activityId = 'xx' AND uid IN (SELECT friendUid FROM usersFriends WHERE uid = 'xx')
Should return 0 if none of their friends are bound to the activity or a positive number if they have friends bound to that activity ...
This should do it:
select
count(*) as CanLike -- 0 if false, >= 1 if true
from
usersFriends uf
join
activitiesUsers au
on
uf.friendUid = au.uid
where
au.id = $activityId
and
uf.uid = $userId
SELECT COUNT(*) AS allowed
FROM userFriends
JOIN activitiesUsers ON (userFriends.uid = activitiesUsers.uid
AND activitiesUsers.activityId = $activity_id)
WHERE userFriends.uid = $user_id
how can i combine these two queries in mysql?
select count(*) as entry_count from tbl_entries where user_id = x
and
select username, avatar from tbl_users where user_id = x
I want one result that combines the result of this 2 queries. Please help me guys!
Thanks!
select username,
avatar,
(select count(*) from tbl_entries where user_id = x) as entry_count
from tbl_users
where user_id = x
select username,
avatar,
(select count(*) from tbl_entries where user_id = x) AS cnt
from tbl_users
where user_id = x
try this one:
SELECT a.username,
a.avatar,
COUNT(*) as entry_count,
FROM tbl_Users a LEFT JOIN tbl_entries b ON
a.user_ID = b.user_ID
WHERE a.user_ID = x
GROUP BY a.username
Try this:
SELECT U.username, U.avatar,
count(*) AS entry_count
FROM tbl_users AS U
LEFT JOIN tbl_entries AS E ON U.user_id = E.user_id
WHERE user_id = x
GROUP BY U.user_id;
SELECT username,
avatar,
(select count(*) from tbl_entries where user_id = U.user_id) AS cnt
FROM tbl_users AS U
WHERE user_id = x