I have a mysql table with items in relation to their order.
CREATE DATABASE IF NOT EXISTS `sqltest`;
USE `sqltest`;
DROP TABLE IF EXISTS `testdata`;
CREATE TABLE `testdata` (
`orderID` varchar(10) DEFAULT NULL,
`itemID` varchar(10) DEFAULT NULL,
`qtyOrdered` int(10) DEFAULT NULL,
`sellingPrice` decimal(10,2) DEFAULT NULL
)
INSERT INTO `testdata`(`orderID`,`itemID`,`qtyOrdered`,`sellingPrice`)
values ('1','a',1,'7.00'),('1','b',2,'8.00'),('1','c',3,'3.00'),('2','a',1,'7.00'),('2','c',4,'3.00');
Intended Result:
A = (1+1)2
B = 2
C = (2+4)6 <- most popular
How do I add up all the qty's for each item and result the highest one?
It should be fairly strait forward but I'm new to SQL and I can't work this one out :S
Solution needs to be mysql and or php.
I guess there needs to be some sort of temporary tally variable for each item ID,
but that seems like it could get messy with too many items.
ANSWER:
(thanks nuqqsa)
SELECT itemID, SUM(qtyOrdered) AS total FROM testdata GROUP BY itemID ORDER BY total DESC LIMIT 1;
How about this:
SELECT itemID, SUM(qtyOrdered) AS total FROM testdata GROUP BY itemID ORDER BY total DESC;
SELECT itemID, SUM(qtyOrdered) as blah FROM sqltest GROUP BY itemID ORDER BY blah DESC should do it
SELECT *
FROM testdata
ORDER BY SUM(gtyOrdered) DESC
GROUP BY itemID
SELECT SUM( qtyOrdered ) AS sum_ordered, itemID
FROM testdata
GROUP BY itemID
ORDER BY sum_ordered
select count(qtyOrdered), qtyOrdered from testdata group by qtyOrdered
Related
I'm trying to limit the number of results of a query based on another table column. For example, I have a table for products and a config table, like this:
tb_product
id | active | name | value | ...
tb_config
max_product | ...
What I'd like to do is something like this
SELECT
a.name, a.value
FROM
tb_product a,
tb_config b
WHERE a.active = 1
LIMIT b.max_product
But I'm getting errors like #1327 - Undeclared variable: b. Is there a way to achieve this result?
Because currently what I'm doing is doing another query to get just the max_product value and then use it as php variable to limit the results, like this:
$limit = "SELECT max_product FROM tb_config";
SELECT name, value FROM tb_product WHERE ativo = 1 LIMIT $limit
Maybe....
SELECT a.name
, a.value
FROM tb_product a
CROSS JOIN (SELECT #Limit:=(SELECT max_product from tb_config))
WHERE a.active = 1
LIMIT #Limit
With help from #ENargit's answer in Variable LIMIT Clause in MySQL, you can do it using a row count variable.
Assuming the following schema:
CREATE TABLE
tb_product
(
id INT PRIMARY KEY AUTO_INCREMENT,
`name` VARCHAR(10),
`value` VARCHAR(10)
);
INSERT INTO
`tb_product`
(`name`, `value`)
VALUES
('Name1','Value1'),
('Name2','Value2'),
('Name3','Value3'),
('Name4','Value4'),
('Name5','Value5'),
('Name6','Value6'),
('Name7','Value7'),
('Name8','Value8'),
('Name9','Value9'),
('Name10','Value10');
CREATE TABLE
`tbl_config`
(
id INT PRIMARY KEY AUTO_INCREMENT,
`type` VARCHAR(10),
`value` INT
);
INSERT INTO
`tbl_config`
(`type`,`value`)
VALUES
('something',10),
('maxrows',7);
You can reference the config table with a subquery:
SELECT * FROM (
SELECT
tb_product.*,
#rownum := #rownum + 1 AS RowNum
FROM tb_product,
(SELECT #rownum := 0) AS CounterTbl
) AS DataTbl
WHERE
RowNum <= (
SELECT
`value`
FROM
`tbl_config`
WHERE
`type` = 'maxrows'
);
Gives you the first 7 rows (according to the config value). You can obviously extend this to do sorting etc.
SQLFiddle: http://www.sqlfiddle.com/#!9/f789e4/2
Hey guys i have a table structure like
CREATE TABLE CUSTOMERS(
ID INT NOT NULL,
NAME VARCHAR (20) NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR (25) ,
SALARY DECIMAL (18, 2),
PRIMARY KEY (ID)
)
INSERT INTO CUSTOMERS (ID,NAME,AGE,ADDRESS,SALARY)
VALUES (1,'aff',2,3,5)
VALUES (2,'afff',1,31,52)
update CUSTOMERS
set NAME = 'somenewname'
where age = 1;
I just want to get output as 'somename'
I have tried creating a column updatedtime with timestamp and used query like
SELECT * FROM CUSTOMERS ORDER BY updatetime DESC LIMIT 1;
But this one shows the whole values ..
I just need only the updated value 'somenewname` as output.
I have also tried using triggers and functions but it didnt helped..
Please help me with a solution..I will accept it as an answer if it helps me ..remember i want an output as a single value like somenewname.
Thanx
The trigger which i have used
CREATE TRIGGER getrandom
AFTER UPDATE ON CUSTOMERS
FOR EACH ROW
BEGIN
UPDATE CUSTOMERS
SET NAME = 'anewname'
WHERE ADDRESS = 3;
END;
Why don't you try to SELECT only the name-column
SELECT name FROM CUSTOMERS ORDER BY updatetime DESC LIMIT 1; //outputs the name
instead of the whole result
SELECT * FROM CUSTOMERS ORDER BY updatetime DESC LIMIT 1;
Your UPDATE statement should look like
update CUSTOMERS
set NAME = 'somenewname',
updatetime = now()
where age = 1;
Now a example of how to get only the name if tables are joined.
SELECT c.name FROM CUSTOMERS as c INNER JOIN orders as o c.id=o.id ORDER BY c.updatetime DESC LIMIT 1;
I am what you would call a 'noob' at MySQL. I can insert/edit/select stuff, but anything more advanced than that stumps me. I have two tables in my database:
Table 'reviews'
id int(11)
review varchar(2500)
game int(11)
user int(11)
title varchar(200)`
and Table 'review_rating'
user int(11)
review int(11) // Corresponds to `reviews.id`
like tinyint(1)
Here is my question: Is it possible to use ORDER BY on the reviews table to order the result by the total number of review_ratings with 'like' = 1 (where 'review' = the id of the 'reviews' table) divided by the total number of review_ratings (where 'review' = the id of the 'reviews' table).
Example:
SELECT *
FROM `reviews`
WHERE `game` = ?
ORDER BY (total number of review_ratings where review = reviews.id and like = 1 /
total number of review_ratings where review = reviews.id)
LIMIT 0, 10
SELECT t.review,
Score = CASE WHEN TotalReviews<> 0 THEN LikedReviews/TotalReviews ELSE NULL END
FROM (
SELECT *,
(SELECT COUNT(*) FROM review_rating WHERE review = r.review) AS TotalReviews ,
(SELECT COUNT(*) FROM review_rating WHERE review = r.review AND like = 1) AS LikedReviews,
FROM review r
WHERE game = ?
)t
ORDER BY t.review, Score
I think it's clearer to put it in the SELECT clause:
SELECT reviews.*,
( SELECT SUM(like) / COUNT(1)
FROM review_ratings
WHERE review = reviews.id
) like_ratio
FROM reviews
WHERE game = ?
ORDER
BY like_ratio DESC
LIMIT 10
;
Notes:
Not tested; I'm away from a MySQL box at the moment.
I think you could move the subquery to the ORDER BY clause if you wanted, but it seems like a useful thing to retrieve, anyway.
I'm not sure how the above will behave if a given review has no ratings. You may need to use a CASE expression to handle that situation.
something like this would order by the total review_rating per review:
select( count(review.id) as 'total' from reviews join review_rating on review.id = review_rating.review group by review.id) order by total
the math is not exactly what you had but hopefully you will get it
so I'm trying to create a ranking system for my website, however as a lot of the records have same number of points, they all have same rank, is there a way to avoid this?
currently have
$conn = $db->query("SELECT COUNT( * ) +1 AS 'position' FROM tv WHERE points > ( SELECT points FROM tv WHERE id ={$data['id']} )");
$d = $db->fetch_array($conn);
echo $d['position'];
And DB structure
`id` int(11) NOT NULL,
`name` varchar(150) NOT NULL,
`points` int(11) NOT NULL,
Edited below,
What I'm doing right now is getting records by lets say
SELECT * FROM tv WHERE type = 1
Now I run a while loop, and I need to make myself a function that will get the rank, but it would make sure that the ranks aren't duplicate
How would I go about making a ranking system that doesn't have same ranking for two records? lets say if the points count is the same, it would order them by ID and get their position? or something like that? Thank you!
If you are using MS SQL Server 2008R2, you can use the RANK function.
http://msdn.microsoft.com/en-us/library/ms176102.aspx
If you are using MySQL, you can look at one of the below options:
http://thinkdiff.net/mysql/how-to-get-rank-using-mysql-query/
http://www.fromdual.ch/ranking-mysql-results
select #rnk:=#rnk+1 as rnk,id,name,points
from table,(select #rnk:=0) as r order by points desc,id
You want to use ORDER BY. Applying on multiple columns is as simple as comma delimiting them: ORDER BY points, id DESC will sort by points and if the points are the same, it will sort by id.
Here's your SELECT query:
SELECT * FROM tv WHERE points > ( SELECT points FROM tv WHERE id ={$data['id']} ) ORDER BY points, id DESC
Documentation to support this: http://dev.mysql.com/doc/refman/5.0/en/sorting-rows.html
Many Database vendors have added special functions to their products to do this, but you can also do it with straight SQL:
Select *, 1 +
(Select Count(*) From myTable
Where ColName < t.ColName) Rank
From MyTable t
or to avoid giving records with the same value of colName the same rank, (This requires a key)
Select *, 1 +
(Select Count(Distinct KeyCol)
From myTable
Where ColName < t.ColName or
(ColName = t.ColName And KeyCol < t.KeyCol)) Rank
From MyTable t
OK, my statement executes well in phpMyAdmin, but not how I expect it in my php page.
This is my statement:
SELECT `egid`, `group_name` , `limit`, MAX( `date` )
FROM employee_groups
GROUP BY `egid`
ORDER BY `egid` DESC ;
This is may table:
CREATE TABLE `employee_groups` (
`egid` int(10) unsigned NOT NULL,
`date` date NOT NULL,
`group_name` varchar(50) NOT NULL,
`limit` smallint(5) unsigned NOT NULL,
PRIMARY KEY (`egid`,`date`)
) ENGINE=MyISAM DEFAULT CHARSET=cp1251;
I want to extract the most recent list of groups, e.g. if a group has been changed I want to have only the last change. And I need it as a list (all groups).
Your query might be broken. You should not select fields that aren't in the group by unless one of the following two conditions apply:
You use an aggregate function.
The value is functionally dependant on the grouped by columns.
The two fields group_name and limit appear to break these rules. This means that you will get indeterminate results for these columns.
If you are trying to select the max per group then you should use a slightly different technique. See Quassnoi's article MYSQL: Selecting records holding a groupwise maximum for a variety of methods you could use.
Here's one way to do it:
SELECT di.*
FROM (
SELECT egid, MAX(date) AS date
FROM employee_groups d
GROUP BY egid
) dd
JOIN employee_groups di
ON di.egid = dd.egid AND di.date = dd.date
aggregate functions will work in mysql, different to the sql standard. to access the value of max(date) from php, you have to alias it:
SELECT `egid`, `group_name` , `limit`, MAX( `date` ) as maxdate
FROM …
you can then select it like any other colum from php with
while($row = mysqli_fetch_row($result)) {
echo htmlspecialchars($row['maxdate']);
}
hope that helps