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;
Related
Following db structure:
Table cms_pages containing pages with id, name, title, etc.
Table cms_pagerows containing rows with a cms_page_id and rank
(Unique index over cms_page_id, rank)
The Pagerows are supposed to contain cols which in turn contain the... content.
I now want to insert a new pagerow into cms_pagerows on an existing page using php.
Ranks are not necessarily consecutive numbers because of the deletion of old pagerows.
For this, I have a function insertRowAt($page_name, $offset) with the following SQL:
INSERT INTO `cms_pagerows` (`cms_page_id`, `rank`)
SELECT `cms_pages`.`id`, `cms_pagerows`.`rank` + 1
FROM `cms_pages`, `cms_pagerows`
WHERE `cms_pages`.`name` = "'.$page_name.'"
AND `cms_pagerows`.`cms_page_id` = `cms_pages`.`id`
ORDER BY `rank` DESC
LIMIT 0, "'.$offset.'"
ON DUPLICATE KEY UPDATE `cms_pagerows`.`rank` = `cms_pagerows`.`rank` + 1
When trying to run it, I get the following error message: "Column 'cms_pagerows.rank' in field list is ambiguous"
The key is to always use table aliases to disambiguate the columns:
INSERT INTO `cms_pagerows`(`cms_page_id`, `rank`)
SELECT p.`id`, pr.`rank` + 1
FROM `cms_pages` p join
`cms_pagerows` pr
on pr.`cms_page_id` = p.`id`
WHERE p.`name` = "'.$page_name.'"
ORDER BY pr.`rank` DESC
LIMIT 0, "'.$offset.'"
ON DUPLICATE KEY UPDATE `rank` = pr.`rank` + 1;
You can also say:
ON DUPLICATE KEY UPDATE `rank` = VALUES(`rank`)
This works because the select is already going to insert the correct rank, so you can just use that value.
try this..
INSERT INTO `cms_pagerows` (`cms_page_id`, `rank`)
SELECT `cms_pages`.`id`, `cms_pagerows`.`rank` + 1 AS rank1
FROM `cms_pages`, `cms_pagerows`
WHERE `cms_pages`.`name` = "'.$page_name.'"
AND `cms_pagerows`.`cms_page_id` = `cms_pages`.`id`
ORDER BY rank1 DESC
LIMIT 0, "'.$offset.'"
ON DUPLICATE KEY UPDATE `rank` = rank1 + 1
two rank fields are conflicting because you are using same name... use AS keyword of mysql..
Well I have this mysql table with numbers in one column and a confirmation boolean of 0 or 1 and I have about 1,000 rows so it's not something I can do manually but anyways...
I want to sort the row by highest value and grab the names of the first 5 people and put those 5 people in another table on a column and then set them to confirmed and continue until there's no one left in the table that isn't confirmed...
ex:
Name:Rank:Confirm
Bob:5000:0
James:34:0
Josh:59:1
Alex:48:0
Romney:500:0
Rolf:24:0
Hat:51:0
so when you run the code it will do the following:
Squad:Name1:Name2:Name3:Name4:Name5
1:Bob:Romney:Hat:Alex:James
(as you can see Josh was excluded and Rolf was too low)
And since Rolf is alone and there are no one else left, he wont be put into a team and will be left unconfirmed...
I'm not really pro at mysql so I was stumped on this and at most was capable of organizing the whole thing by rank and that's it ._.
edit:
The terrible attempt I had at this:
<?php
$parse = mysql_query("SELECT MAX(rank) AS rank FROM users AND confirm='0'");
mysql_query("Insert into squad (nameone)values($parse)");
mysql_query("Update squad set confirm = '1' where name = $parse");
?>
Assuming confirm will have only either 1 or 0.
CREATE TABLE table2 (id INT PRIMARY KEY AUTO_INCREMENT, name varchar(255));
CREATE PROCEDURE rank()
BEGIN
DECLARE count INT DEFAULT 1;
WHILE count > 0 DO
UPDATE table1 SET Confirm=2 WHERE Confirm=0 ORDER BY Rank DESC LIMIT 5;
INSERT INTO table2 (SELECT GROUP_CONCAT(Name) FROM table1 WHERE Confirm=2);
UPDATE table1 SET Confirm=1 WHERE Confirm=2;
SELECT count(*) FROM table1 WHERE Confirm=0;
END WHILE;
END;
Call the procedure rank() when ever you want
CALL rank();
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
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
Hello i have a question on picking random entries from a database. I have 4 tables, products, bids and autobids, and users.
Products
-------
id 20,21,22,23,24(prime_key)
price...........
etc...........
users
-------
id(prim_key)
name user1,user2,user3
etc
bids
-------
product_id
user_id
created
autobids
--------
user_id
product_id
Now a multiple users can have an autobid on an product. So for the next bidder I want to select a random user from the autobid table
example of the query in language:
for each product in the autobid table I want a random user, which is not the last bidder.
On product 20 has user1,user2,user3 an autobidding.
On product 21 has user1,user2,user3 an autobidding
Then I want a resultset that looks for example like this
20 – user2
21 – user3
Just a random user. I tried miximg the GOUP BY (product_id) and making it RAND(), but I just can't get the right values from it. Now I am getting a random user, but all the values that go with it don't match.
Can someone please help me construct this query, I am using php and mysql
The first part of the solution is concerned with identifying the latest bid for each product: these eventually wind up in temporary table "latest_bid".
Then, we assign randon rank values to each autobid for each product - excluding the latest bid for each product. We then choose the highest rank value for each product, and then output the user_id and product_id of the autobids with those highest rank values.
create temporary table lastbids (product_id int not null,
created datetime not null,
primary key( product_id, created ) );
insert into lastbids
select product_id, max(created)
from bids
group by product_id;
create temporary table latest_bid ( user_id int not null,
product_id int not null,
primary key( user_id, product_id) );
insert into latest_bid
select product_id, user_id
from bids b
join lastbids lb on lb.product_id = b.product_id and lb.created = b.created;
create temporary table rank ( user_id int not null,
product_id int not null,
rank float not null,
primary key( product_id, rank ));
# "ignore" duplicates - it should not matter
# left join on latest_bid to exclude latest_bid for each product
insert ignore into rank
select user_id, product_id, rand()
from autobids a
left join latest_bid lb on a.user_id = lb.user_id and a.product_id = lb.product_id
where lb.user_id is null;
create temporary table choice
as select product_id,max(rank) choice
from rank group by product_id;
select user_id, res.product_id from rank res
join choice on res.product_id = choice.product_id and res.rank = choice.choice;
You can use the LIMIT statement in conjunction with server-side PREPARE.
Here is an example that selects a random row from the table mysql.help_category:
select #choice:= (rand() * count(*)) from mysql.help_category;
prepare rand_msg from 'select * from mysql.help_category limit ?,1';
execute rand_msg using #choice;
deallocate prepare rand_msg;
This will need refining to prevent #choice becoming zero, but the general idea works.
Alternatively, your application can construct the count itself by running the first select, and constructing the second select with a hard-coded limit value:
select count(*) from mysql.help_category;
# application then calculates limit value and constructs the select statement:
select * from mysql.help_category limit 5,1;