Hello I would like to know how I can realizes query selection inside echo of already processed query.
This is my firs Mysql Query
SELECT * FROM cursos_modulos
foreach($result as $row)
{
$id = $row['id'];
echo"
Here where the echo goes I have to make the other query which is:
SELECT COUNT(users.userID)
FROM users
INNER JOIN subscriptions
ON users.userID = subscriptions.user_id
WHERE subscriptions.curso_id = $id
and at the end to put the result of this query
foreach($result as $rowc)
.$rowc[0]."};
Any help how I can achive this goal will be very welcome. Question is simple. First Select Selects the Cours with it's unique ID. which ID have to be used in the second, third and else... queries. Which queries are like the second one. So First Select Course and then Select different parameters from this course based on this ID. at the end dump results of each of the selections with different indications"
Do it all in one query:
SELECT c.*, count(s.curso_id) as count
FROM cursos_modulos AS c
LEFT JOIN subscriptions AS s ON s.curso_id = c.id
LEFT JOIN users AS u ON u.userID = s.user_id
The LEFT JOIN is needed to get 0 for the count if there are no matching rows in subscriptions.
To include a second count of approved subscriptions:
SELECT c.*, count(s.curso_id) as count, SUM(IF(s.approved = 'approved', 1, 0)) AS count_approved
FROM cursos_modulos AS c
LEFT JOIN subscriptions AS s ON s.curso_id = c.id
LEFT JOIN users AS u ON u.userID = s.user_id
Related
I have two tables: publick_feed and users
I want to SELECT all from public_feed and also SELECT a three columns from users whose id is the same of user_id in public_feed
and assign the rows returned from public_feed to the column in users table ( correspondent)
I try this:
<?php
$sql = "
SELECT * FROM public_feed
WHERE user_id IN
(SELECT id FROM users) AND
(SELECT Firstname,Lastname,Avatar FROM users WHERE id IN(SELECT user_id FROM public_feed))
";
$query = mysqli_query($dbc_conn,$sql);
if(mysqli_num_rows($query) > 0){
while($row = mysqli_fetch_assoc($query)){
//echo rows with correspondent details from the users table
echo $row['user_id'];
}
}
<?
Please any help will be much appreciated.
Thank you.
Or version with left join in case if there is no user in public_feed, and you still want to fetch user data
SELECT
u.*, f.*
FROM
public_feed f LEFT JOIN
users u ON f.user_id = u.id;
Because author asked for explanation, here it is:
First we are going to use table name alias to make query shorter
public_feed f
and
users u
we are saying that want to refer to tables with an alias. Of course * means that we want to select all columns
SELECT users.*, public_feed.*
is equal to
SELECT u.*, f.*
Of course you can use any other letters as an alias
Next we are saying that public_feed.user_id must be equal to users.id. But when public feed entry does not exists just display columns with null values. This is why we are using LEFT JOIN instead of INNER JOIN. In general JOINS are used to fetch related data from more than one related tables.
ON keyword is saying values from which columns in the tables must be equal to satisfy the request
I think doing a join would be cleaner than using a complicated subquery:
SELECT u.Firstname,
u.Lastname,
u.Avatar,
COALESCE(pf.User_id, 'NA'),
COALESCE(pf.Post, 'NA'),
COALESCE(pf.Date, 'NA')
FROM users u
LEFT JOIN public_feed pf
ON u.Id = pf.User_id
I chose a LEFT JOIN of users against public_feed on the assumption that every feed will have an entry in the users table, but not necessarily vice-versa. For those users who have no feed entries, NA would appear in those columns and that user would appear in only a single record.
I am running a MySQL query to get all "users" with current orders.
(It is possible for a user to have more than 1 associated orders in the db/query).
However i also want to get the total order value for each user and total order count for each user that is being returned (within the below query).
I could do these calculations in PHP, but feel it is possible and would be neater all done within the same SQL query (if possible).
This is the basic query with no attempt to make the above calculations
SELECT u.UserID, u.UserName,
o.OrdersID, o.OrderProductName, o.OrderProductQT, o.OrderTotalPrice, o.tUsers_UserID, o.tOrderStatus_StatusID, o.OrderDate, o.OrderDateModified, o.OrderVoid, o.tProducts_ProductID,
os.OrderStatusName,
ud.UserDetailsName, ud.UserDetailsPostCode,
p.ProductName, p.ProductImage1
FROM tusers u
INNER JOIN torders o ON o.tUsers_UserID = u.UserID
INNER JOIN torderstatus os ON os.OrderStatus_StatusID = o.tOrderStatus_StatusID
INNER JOIN tuserdetails ud ON ud.tUsers_UserID = u.UserID
LEFT JOIN tproducts p ON p.ProductID = o.tProducts_ProductID
WHERE o.tOrderStatus_StatusID = ?
GROUP BY u.UserID
ORDER BY OrdersID DESC
I have tried various nested select queries, but none of them work (right)
Is what i want to do possible in SQL or should i just do it all in PHP once i have the returned query results?
Any advice is much appreciated
You can embed the slightly modified queries into another query. For instance:
SELECT userid, SUM(orderid) FROM orders GROUP BY userid
and
SELECT userid, SUM(distinct productid)
FROM
orders o
INNER JOIN orderlines ol on ol.orderid = o.orderid
GROUP BY
userid
can be combined to:
SELECT
u.userid
u.fullname,
(SELECT SUM(orderid)
FROM orders o
WHERE o.userid = u.userid) as ORDERCOUNT,
(SELECT SUM(distinct productid)
FROM
orders o
INNER JOIN orderlines ol on ol.orderid = o.orderid
WHERE
o.userid = u.userid) as UNIQUEPRODUCTS
FROM
users u
Note that the latter query will return all users and will return NULL for ORDERCOUNT or UNIQUEPRODUCTS when the subquery doesn't return anything (when a user doesn't have orders). Also, the query will fail when a subquery returns more than 1 row, which should never happen in the example I posted.
i am trying to get number of posts that i have
Here is my query
$Query="
SELECT t.*,u.*,c.*
FROM posts as t
LEFT JOIN relations as r on r.post_id = t.post_id
LEFT JOIN users as u on t.auther_id = u.auther_id
LEFT JOIN categories as c on c.cate_id = r.cate_id
GROUP BY t.post_id
";
$Query=mysql_query($Query);
$numberOfPosts=mysql_num_rows($Query);
This query is works very well
but i am trying to convert it, i want make it faster
i want use count(*) instead of t.*
because when i use t.*, it gets the full data of posts and categories
but i want to get count only, So i decided to use count(*) but i don't know how to use it with query like this
Edit
i've replaced SELECT t.*,u.*,c.* with SELECT count(t.*)
But i got mysql Error Warning: mysql_fetch_assoc(): supplied argument
Edit 2:
i am trying SELECT count(t.post_title)
I Got this results
Array ( [count(t.post_id)] => 10 )
But i have only 2 posts!
$Query="
SELECT t.*,u.*,c.*
FROM posts as t
LEFT JOIN relations as r on r.post_id = t.post_id
LEFT JOIN users as u on t.auther_id = u.auther_id
LEFT JOIN categories as c on c.cate_id = r.cate_id
GROUP BY t.post_id
";
$Query=mysql_query($Query);
$numberOfPosts=mysql_num_rows($Query);
Let's take a step back and analyze this query for a moment.
You're selecting everything from three out of four tables used in the query. The joins create some logic to limit what you select to the proper categories, authors, etc. At the end of the day you are getting a lot of data from the database, then in PHP simply asking it how many rows were returned (mysql_num_rows). Instead, what #Dagon is trying to suggest in comments, is that you have MySQL simply count the results, and return that.
Let's refactor your query:
$query = "
SELECT COUNT(t.post_id) AS qty
FROM posts as t
LEFT JOIN relations AS r ON r.post_id = t.post_id
LEFT JOIN users AS u ON t.auther_id = u.auther_id
LEFT JOIN categories AS c ON c.cate_id = r.cate_id
GROUP BY t.post_id
";
$result = mysql_query($query);
$result_row = mysql_fetch_assoc($result);
$numberOfPosts = $result_row['qty'];
(You could also use Barattlo's custom execute_scalar function to make it more readable.)
I would need to see your table structures to be of more help on how to optimize the query and get the desired results.
try doing this:
$Query="
SELECT count(t.*) as count_all
FROM posts as t
LEFT JOIN relations as r on r.post_id = t.post_id
LEFT JOIN users as u on t.auther_id = u.auther_id
LEFT JOIN categories as c on c.cate_id = r.cate_id
GROUP BY t.post_id
";
$Query=mysql_query($Query);
$numberOfPosts=mysql_num_rows($Query);
You want to do
SELECT count(t.id) AS count FROM ....
//do query with PDO or whatever you are using
$rows = mysql_fetch_assoc();
$num_rows = $rows['count'];
You should probably simply use
SELECT count(*) as postingcount FROM posts
Why?
Because you do not have a WHERE clause, so there are no restrictions. Your JOINS do not ADD more rows to the resultset, and in the end your GROUP BY merges every duplicate occurance of a post_id that might have occurred because of joining back into one row. The result should only be counted, so assuming that the real number you want to know is the number of data sets inside the table posts, you do not need any join, and doing count(*) really is a very fast operation on tables in MySQL.
Remember to check if mysql_query returns false, because then you have to check mysql_error() and see why your query has an error.
I try to use this Query to get Number of Records bu tits not display count in phpMyAdmin
And also give me the wrong result when i try to remove LIMIT from Query..
SELECT COUNT(*) as `num` FROM fm_detail
LEFT JOIN lang ON lang.l_id = fm_detail.language_id
LEFT JOIN country ON country.c_id = fm_detail.country_id
LEFT JOIN users ON users.usr_id = fm_detail.submitter_id
LEFT JOIN category ON category.cat_id = fm_detail.category_id
INNER JOIN city ON fm_detail.city_fm = city.city_id
where 1=1 AND fm_detail.category_id = '1' LIMIT 10 , 5
This query did not give me any Record Count..
But when i use..
SELECT * FROM fm_detail
LEFT JOIN lang ON lang.l_id = fm_detail.language_id
LEFT JOIN country ON country.c_id = fm_detail.country_id
LEFT JOIN users ON users.usr_id = fm_detail.submitter_id
LEFT JOIN category ON category.cat_id = fm_detail.category_id
INNER JOIN city ON fm_detail.city_fm = city.city_id
where 1=1 AND fm_detail.category_id = '1' LIMIT 10 , 5
This give me the Records list in PHPMYADMIN..
I don't know how to use this query to fix my problem.
Please help me asap..
Thanks,
Because you use COUNT function (which in your case returns one row) and LIMIT clause that starts from 10 record. So, you do not get any records at all.
About the LIMIT... maybe select distinct will help to get the right count. Joins sometimes create duplicated rows.
so I'm having trouble selecting a field only if another fields value is not equal to 0.
So, here's what's going on.
I have 3 tables, they are - users, schools, campuses
And basically, I need to select a single users data from these 3 tables. I'd like to only select the campus_name field from campuses if the users.campus_id field is not 0.
So, something pseudo coded like this might give you a better idea..
The query is being passed in a $id variable, that has some user's id.
SELECT users.*, schools.*, (if(users.campus_id != 0) then campuses.campus_name)
FROM users, schools, campuses
WHERE users.id = '$id' (if(users.campus_id != 0) then AND campuses.id = users.campus_id)
SELECT *
FROM schools,
users LEFT OUTER JOIN campuses
ON users.campus_id != 0
AND users.campus_id = campuses.id
WHERE users.school_id = schools.id
So you are joining three tables together, you always expect a user to have a school, but they may not have a campus, and if this is the case, obviously nothing should be displayed.
The best you can do is acheive this with a LEFT JOIN on campuses.
An example based on your pseudo code below:
SELECT u.*, s.*, c.campus_name
FROM users u
INNER JOIN schools s ON u.school_id = s.school_id
LEFT JOIN campuses c ON u.campus_id = c.campus_id
WHERE u.user_id = $userId
If I understood you correctly, you want ALL the information displayed, but to display campus name ONLY if it exists? If so, I believe the following statement should do the trick:
SELECT `u`.* `s`.* if(`c`.`campus_name` != 0, `c`.`campus_name`, "") as `campus`
FROM `users` as `u`
INNER JOIN `schools` as `s` ON `u`.`school_id` = `s`.`school_id`
LEFT JOIN `campuses` as `c` ON `u`.`campus_id` = `c`.`campus_id`
WHERE `u`.`user_id` = $user_id;
Untested, written from the top of my head, could be errors in there