MySQL Query w/ 2 tables to get the desired results - php

I am trying to pull in the related postings based on the posting category. So where all category ids match the category id field.
Additional clarification:
I've been experimenting all morning and still no luck, and this is where I am at now. Note the $CatID in the ON clause is from a previous query above this one and the value is correct.
$sql = "
(SELECT
a.id,
a.Price,
a.City,
a.Country,
a.Title,
a.Description,
a.Category, // contains the corresponding ads_cate.id.
a.recdate,
c.cateName,
'item' AS type FROM ads_list AS a
LEFT OUTER JOIN ads_cate AS c
ON $CatID=a.Category
WHERE to_days(now())<=(to_days(recdate)+14)
ORDER BY RAND())
";
And as tested:
echo $CatID . $row['Category']; // Outputs 3 3 which is correct. Category is 3 ads_cate id is also 3 for this record.
My results is pulling in duplicates and ALL ads regardless of Category.

If every ad has a category, and assuming your ads_cate table has an id field:
$sql = "
SELECT
a.id,
a.Price,
a.City,
a.Country,
a.Title,
a.Description,
a.Category, // contains the corresponding ads_cate.id.
a.recdate,
c.cateName,
'item' AS type
FROM ads_list AS a
LEFT OUTER JOIN ads_cate AS c
ON c.id=a.Category
WHERE to_days(now())<=(to_days(recdate)+14)
AND a.Category = $CatID
ORDER BY RAND()
";

Although I don't understand your question, when using join, you can use SELECT DISTINCT to stop the duplicates. Beyond that, I don't understand the question.

This is my working code. Had to modify some based on bfavaretto's suggestion, but it's working as expected now:
$sql = "
(SELECT
a.id,
a.Price,
a.City,
a.Country,
a.Title,
a.Description,
a.Category,
a.images,
a.recdate,
a.images,
a.image2,
a.image3,
a.image4,
a.imgWidth,
a.imgHeight,
a.ftype,
c.id,
c.cateName,
a.email,
'item' AS type FROM ads_list
AS a LEFT OUTER JOIN ads_cate
AS c ON c.id=a.Category WHERE to_days(now())<=(to_days(recdate)+14) AND a.Category = $CatID ORDER BY RAND())";

Related

Left Join - Select ALL from left table but select only the latest from right table

I have 2 tables, borrowers and loans. I want to display on the main page the list of ALL borrowers with or without loans. If with loan, display the newest one.
I have the following sql query, basically it returns the above description except it displays the very first loan of the borrower instead of the latest one.
(Side note: I used GROUP BY to avoid duplicates. Without it the query returns duplicated borrower names if they have multiple loans. Just wanted to know if this is an efficient way of doing so.)
SELECT b.b_id,
b.isdeleted,
b.picture,
b.firstname,
b.middlename,
b.lastname,
b.address,
b.contactno,
b.birthday,
b.businessname,
b.occupation,
b.comaker,
b.comakerno,
b.remarks,
b.datecreated,
b.activeloan,
l.l_id,
l.amount,
l.payable,
l.balance,
l.mode,
l.term,
l.interestrate,
l.amortization,
l.releasedate,
l.duedate,
l.status,
l.c_id
FROM borrowers as b
LEFT JOIN loans as l ON b.b_id = l.b_id
WHERE b.isdeleted = 0
GROUP BY b.b_id
It seems the below query does exactly what i wanted.
I added the below subquery on the "ON" clause.
(SELECT MAX(l_id)
FROM jai_db.loans as l2
WHERE l2.b_id = b.b_id LIMIT 1)
SELECT b.b_id, b.isdeleted, b.picture, b.firstname, b.middlename, b.lastname, b.address, b.contactno,
b.birthday, b.businessname, b.occupation, b.comaker, b.comakerno, b.remarks, b.datecreated, b.activeloan,
l.l_id, l.amount, l.payable, l.balance, l.mode, l.term, l.interestrate, l.amortization,
l.releasedate, l.duedate, l.status, l.c_id
FROM jai_db.borrowers as b
LEFT JOIN jai_db.loans as l
ON l.l_id = (SELECT MAX(l_id)
FROM jai_db.loans as l2
WHERE l2.b_id = b.b_id LIMIT 1)
WHERE b.isdeleted = 0

How to show name of course in INNER JOIN?

I have two tables: users and courses. Inside users table i have filed course where i have course id. Inside courses table i have just ID and NAME.
I need to get popular course. I do request:
SELECT u.course, COUNT(*) as freq FROM users u INNER JOIN courses c ON u.course = c.id GROUP BY u.course
As a result: id => freq. But i need to replace ID to NAME of course. How?
Thanks.
You don't say what database you use, but I would assume you can use CTEs since most modern databases do. Your query can be written as:
with x as (
select course, count(*) as freq from users group by course
),
y as (
select max(freq) as max_freq from x
)
select c.name, x.freq
from x
join y on x.freq = y.max_freq
join courses c on c.id = x.course
This query has the [desirable?] side effect that it shows more than one course, if there are more than one tied in first place.
Add c.name to both the SELECT clause and the GROUP BY clause.
SELECT u.course, c.name, COUNT(*) as freq
FROM users u
INNER JOIN courses c
ON u.course = c.id
GROUP BY u.course, c.name;
Demo: https://dbfiddle.uk/?rdbms=mariadb_10.3&fiddle=02a41e0f1e6407e516e91c49b4bdc1d2
SELECT u.course, COUNT(*) as freq, c.name FROM users u INNER JOIN courses c ON u.course = c.id GROUP BY u.course
If your DBMS supports row_number this will be suitable:
select t.id, c.name, t.cnt
from course c
join (
select c.id, count(1) cnt, ROW_NUMBER() over(order by count(1) desc) rn
from users u
join course c on c.id = u.course
group by id
)t on t.id = c.id and t.rn = 1

MySQL query to order results by number of votes in another table for the specifc result/row

Okay, so I have a query below I am trying to get to work.
Basically everything works up until the inner join of the 'votes' table. What I am trying to do is order the results of this query in accordance with the number of votes each content row has in another table called votes. I know I'm not too far off from what I need to do!
Thanks in advance!!
mysql_query("
SELECT content.id, content.type, content.title, content.url, users.username
FROM content
INNER JOIN users ON content.uploaderuid = users.id
INNER JOIN votes ON votes.id = content.id
WHERE (content.type = 'pic')
ORDER BY COUNT(votes.id) DESC");
Try doing:
SELECT content.id, content.type, content.title, content.url, users.username
FROM content
INNER JOIN users ON content.uploaderuid = users.id
INNER JOIN (
SELECT id,COUNT(*) as voteCount
FROM votes
GROUP BY id
) v ON v.id = content.id
WHERE (content.type = 'pic')
ORDER BY v.voteCount DESC
When you do an INNER JOIN with votes table directly, if you have multiple occurrences of the same id, you will get a lot more rows than before you did the JOIN.
If you are only interested in the number of votes for each id, by doing a JOIN with a subquery that calculates the count of votes for each id, will leave your previous query results as they were, and lets you use the voteCount to order by it.
You could try this:
SELECT c.id, c.type, c.title, c.url, u.username, COUNT(v.id) votes
FROM content c
INNER JOIN users u ON c.uploaderuid = u.id
INNER JOIN votes v ON v.id = c.id
WHERE c.type = 'pic'
GROUP BY c.id, c.type, c.title, c.url, u.username
ORDER BY votes DESC
Here is the SQL Fiddle that demonstrates the below query:
SELECT c.id, c.type, c.title, c.url, u.username, COUNT(v.id)
FROM content AS c
INNER JOIN users AS u ON c.uploaderuid = u.id
INNER JOIN votes AS v ON v.id = c.id
WHERE c.type = 'pic'
GROUP BY c.id, c.type, c.title, c.url, u.username
ORDER BY COUNT(v.id) DESC

Mysql Ranking based on Category and Branch

I'm having a hard time figuring out and trying how to fix this.
Can you help me give a logic or idea how can get the ranking of each category for each branch based on sales?
For example:
Rank 1 for branch_code_id = 9 is Accicular since it has 300,000 sales
Rank 2 for branch_code_id = 9 is WLO since it has only 200,000
sales.
Same as with other branches. I only need the rank of category for each branch_code_id.
I can't figure out how to loop this one. Rank will be placed in the "r" column as you can see in the excel output.
By the way, here's the sql statement i used to get the result you see in the screenshot.
SELECT
a.id,
a.date,
a.branch_code_id,
SUM(b.amount),
c.category
FROM
sales_add_h AS a
INNER JOIN sales_add_i AS b ON a.id = b.sales_h_id
INNER JOIN control_panel_item_create AS c ON b.item_code_id = c.id
GROUP BY c.category, a.branch_code_id, b.amount
ORDER BY SUM(b.amount) DESC
Thanks Guys!
Try this query
SELECT
#rn:=if(#prv=branch_code_id, #rn+1, 1) as rId,
#prv:= branch_code_id as branch_code_id,
val,
id,
date,
category
FROM
(SELECT
a.id,
a.date,
a.branch_code_id,
SUM(b.amount) as val,
c.category
FROM
sales_add_h AS a
INNER JOIN
sales_add_i AS b ON a.id = b.sales_h_id
INNER JOIN
control_panel_item_create AS c ON b.item_code_id = c.id
GROUP BY
c.category, a.branch_code_id, b.amount
ORDER BY
a.branch_code_id, SUM(b.amount) DESC)tmp
JOIN
(SELECT #rn:=0, #prv:=0)t
SQLFIDDLE to understand how ranking works.
I have done ranking for each branch_id as you have mentioned, if you want to rank for each category in a particular branch than you need to add another variable which stores the category and compare it within the if clause and also need to sort data within inner query accordingly order by c.category, a.branch_code_id, SUM(b.amount) DESC

MySQL joining tables with ORDER BY gives unexpected result

I have this database design:
**users_tbl**
id
username
name
**posts_tbl**
id
url
users_id *FK REFERENCE to users table*
**posts_contents_tbl**
id
posts_id *FK REFERENCE to posts table
title
description
date
views
click
isDeleted
I'm using this query
SELECT a.name,a.username,c.*
FROM users_tbl a
LEFT JOIN posts_tbl b ON a.id = b.users_id
LEFT JOIN posts_contents_tbl c ON b.id = c.posts_id
ORDER BY c.id ASC
Why I try to run this query it gives me NULL results, sample output is like this
But when I try to remove the ORDER BY c.id ASC it gives me this output:
That's not my expected result.
My expected result would be it will display the posts_contents_tbl in Ascending order at the same time it won't show some null values. Some users in my database doesn't have posts data in the posts_tbl so they should not show too.
How would I do that one? Your help would be greatly appreciated and rewarded!
Thanks!
PS: I already have thousands record in my database.
In that case, you have to use INNER JOIN instead of LEFT JOIN because you only want users with posts to show. The reason why there are Null values is because the records are based on table users_tbl and you've mentioned that some of them have no post. Right?
Try this:
SELECT a.name,
a.username,
c.*
FROM users_tbl a
INNER JOIN posts_tbl b
ON a.id = b.users_id
INNER JOIN posts_contents_tbl c
ON b.id = c.posts_id
ORDER BY c.`date` DESC
I think this is what you are looking for:
SELECT a.name,a.username,c.*
FROM users_tbl a
INNER JOIN posts_tbl b
ON a.id = b.users_id
LEFT JOIN posts_contents_tbl c
ON b.id = c.posts_id
ORDER BY IFNULL(c.id, 0) ASC;
If you really needs that posts_tbl data should not display if not available.And all data of posts_contents_tbl then you need a RIGHT JOIN and INNER JOIN .
The Query like :-
SELECT a.name,a.username,c.*
FROM users_tbl a
INNER JOIN posts_tbl b ON a.id = b.users_id
RIGHT JOIN posts_contents_tbl c ON b.id = c.posts_id
ORDER BY c.id ASC;

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