I am trying to generate a random integer for each row I select between 1 and 60 as timer.
SELECT downloads.date, products.*, (FLOOR(1 + RAND() * 60)) AS timer
I have searched and keep coming up to this FLOOR function as how to select a random integer in a range. This is giving me a 1 for every row.
What am I missing?
I am on mysql 5.0.75
Heres the rest of the query I belive it might be a nesting issue
SELECT *
FROM (
SELECT downloads.date, products.*, FLOOR(1 + (RAND() * 60)) AS randomtimer,
(
SELECT COUNT( * )
FROM distros
WHERE distros.product_id = products.product_id
) AS distro_count,
(SELECT COUNT(*) FROM downloads WHERE downloads.product_id = products.product_id) AS true_downloads
FROM downloads
INNER JOIN products ON downloads.product_id = downloads.product_id
) AS count_table
WHERE count_table.distro_count > 0
AND count_table.active = 1
ORDER BY count_table.randomtimer , count_table.date DESC LIMIT 10
This is working for me. Your mysql version maybe?
SELECT id, (FLOOR( 1 + RAND( ) *60 )) AS timer
FROM users
LIMIT 0 , 30
The output of the RAND function will always be a value between 0 and 1.
Try this:
SELECT downloads.date, products.*, (CAST(RAND() * 60 AS UNSIGNED) + 1) AS timer
Old question, but always actual problem.
Here a way to create a MySQL function random_integer() based on manual :
CREATE FUNCTION random_integer(value_minimum INT, value_maximum INT)
RETURNS INT
COMMENT 'Gets a random integer between value_minimum and value_maximum, bounds included'
RETURN FLOOR(value_minimum + RAND() * (value_maximum - value_minimum + 1));
SELECT ALL random_integer(1, 60) AS timer;
I'm running your query and it does give me a random number for each row.... maybe has something to do with the name of the random (timer)?
You can increase the number multiplied by the number of records in the table.
SELECT id,
(FLOOR( (SELECT MIN(id) FROM your_table ) + RAND( ) * 1000000 ) ) AS timer
FROM your_table
LIMIT 0 , 30
Related
I have a table with id from 1 to 10, now I need to random some data from 1 to 2, 3 to 5 and 6 to 10, such as random select 1,4,9, is there any way using one sql to resolve it?
SELECT tablename.*
FROM tablename
JOIN ( SELECT ROUND(1 * RAND() + 1) random UNION ALL
SELECT ROUND(2 * RAND() + 3) UNION ALL
SELECT ROUND(4 * RAND() + 6) ) randoms ON tablename.id = randoms.random
I want
example 10% of records in table
not 10 records
This query run in SQL Server
select top 10 percent * from tablename
Why this query in MySQL do not run?
select top 10 percent * from tablename
You could do it with a subquery, this is pretty basic since you want everything in one table:
SELECT *
FROM (
SELECT tablename.*, #counter := #counter +1 AS counter
FROM (select #counter:=0) AS initvar, tablename
ORDER BY value DESC
) AS X
where counter <= (10/100 * #counter);
ORDER BY value DESC
For MySQL use order by or limit
select * from tablename order by percent desc limit 10
TOP clause works on MSSQL server not sql.
What I am trying to get is to send a request to DB that will:
1 count all rows
2 return 10 rows
SELECT count( * ) AS 'total'
FROM stuff
WHERE usr = '65'
LIMIT 10
So it is supposed to return 10 results PLUS 'total' with the number of all rows.
So far it returns the counted amount of rows only....
-- count records first
SET #total = (
SELECT count( * ) AS 'total'
FROM `stuff`
WHERE `usr` = '65'
);
-- then, select your ten records and include the total from previous operation
SELECT *, #total
FROM `stuff`
WHERE `usr` = '65'
LIMIT 10
You'll need to split the 2 concerns out, and then recombine them:
SELECT s.col1, s.col2, s.col3, x.total
FROM `stuff` s
CROSS JOIN
(
SELECT count(*) AS total
FROM `stuff`
WHERE `usr` = '65'
) x
WHERE s.`usr` = '65'
LIMIT 10;
Fiddle here
RDBMs like SqlServer and Oracle allow for CTE's which would allow you to DRY up the repeated select ... where. Some options in MySql here
If you want all rows to be counted and limit the result to 10 then you can do it the following way
SELECT SQL_CALC_FOUND_ROWS * FROM `stuff` WHERE `usr` = '65' LIMIT 10
SELECT FOUND_ROWS();
I have a simple MySQL query like this:
SELECT * ,
( MATCH (table.get) AGAINST('playstation ' IN BOOLEAN MODE) )
+ ( table.get LIKE '%playstation%') AS _score
FROM table
JOIN users on table.id_user = users.id
WHERE table.expire_datetime > 1375997618
HAVING _score > 0
ORDER BY RAND(table.id) ,_score DESC ;
If I run this query in MySQL, it returns usually more then 1 record, now I would like to LIMIT 1 and get one of them randomly, not always the same record.
Is it possible?
select * from <my_table>
ORDER BY RAND()
LIMIT 4
You would quit seeding the random number generator. My guess is that it is returning the first table id encountered, so the numbers are generated in the same sequence:
SELECT * ,
( MATCH (table.get) AGAINST('playstation ' IN BOOLEAN MODE) )
+ ( table.get LIKE '%playstation%') AS _score
FROM table
JOIN users on table.id_user = users.id
WHERE table.expire_datetime > 1375997618
HAVING _score > 0
ORDER BY RAND()
LIMIT 1;
As I understand problem in ,_score ?
Try this:
Select * FROM (
***your sql query***
) as t
ORDER BY RAND()
LIMIT 1
MySQL what's the best way to select X random entries (rather than just one) - optimization for heavy use, i.e. on main page of a domain.
Supposedly just blindly using MySQL rand() is going to make this rather scary for large databases - please give me a better optimization answer than that!
the solution is use php
look at this article that choose the solution number 3 as faster
http://akinas.com/pages/en/blog/mysql_random_row/
Solution 3 [PHP]
$offset_result = mysql_query( " SELECT FLOOR(RAND() * COUNT(*)) AS `offset` FROM `table` ");
$offset_row = mysql_fetch_object( $offset_result );
$offset = $offset_row->offset;
$result = mysql_query( " SELECT * FROM `table` LIMIT $offset, 1 " )
the
Solution 4 [SQL] (Second in fast)
SELECT * FROM `table` WHERE id >= (SELECT FLOOR( MAX(id) * RAND()) FROM `table` ) ORDER BY id LIMIT 1;
I had an issue with the ids. The id was auto generated but the minimum id was very large with respect to the number of total records. So I made a little changes to make the query more randomized, but a little slower though.
SELECT * FROM 'table' WHERE id >= (SELECT (FLOOR( MAX(id) * RAND()) + MIN(id)) FROM 'table' ) ORDER BY id LIMIT 10