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Mysql: get 10 random rows among 50 rows (the rest excluded by WHERE) from 600k rows fast
by Mason McCuskey in Network & Servers

My question is based on the SO MySQL select 10 random rows from 600K rows fast.
It is known


SELECT column FROM table
ORDER BY RAND()
LIMIT 10

is too slow for huge tables, another tricks and methods are used to extract some rows.


But what if I use WHERE:


SELECT column FROM table
WHERE colA=123
ORDER BY RAND()

Change some rows to columns, keep some rows in rows in R dataframe
by Matthew in Web Design

Every time I look at this problem, my brain shuts down. I think it will be simple for some one else.
I have a very large dataframe that can be simplified as so:


day subject y variable
1 a 2.1
1 b 3.5
1 c 2.2
2 a 3.3
2 b 4.5
2 c 3.8
3 a 5.1
3 b 2.8
3 c 2.3
4 a 4.2
4 b 1.9
4

I want to generate two expandable sections with 4 rows and 2 rows .The following code generates two expandable section with 4 rows each
by Peter H in Mobile Programming

In the following example section 1 and 2 expandable.But every expandable section has 4 cells each .I need a way to fit 4 rows in section 1 and 2 rows in section 2.The first method specifies the rows to be expanded and the rest are tableview delegate and datasource methods


- (BOOL)tableView:(UITableView *)tableView canCollapseSection:(NSInteger)section
{
if

How to sort only odd rows (and keep even rows after corresponding odd rows) using jquery?
by Carbito in Coding

I have table with odd rows with basic info and even rows with some content:


Title Category AnotherColumn
Title1 Category1 AnotherColumn1
Content1
Title2 Category2 AnotherColumn2
Content2
Title3 Category3 AnotherColumn3
Content3
Title4 Category4 AnotherColumn4
Content4

Using javascript to show/hide content rows, but no


Flex DataGrid Rows Draging, need to customize background color of dragged rows
by nickthecook in Programming Languages

In flex DataGrid i have enabled drag and drop of rows to enable user reorder the rows.
functionality is working fine.
Default behavior of drag rows is transparent background with all column text.


Just need to highlight background color of rows which is being dragged?


Is it possible to write a SQL query to return specific rows, but then join some columns of those rows with another table?
by cthulhup in Databases

I'm having trouble wrapping my head around how to write this query.


A hypothetical problem that is that same as the one I'm trying to solve:


Say I have a table of apples. Each apple has numerous attributes, such as color_id, variety_id and the orchard_id they were picked from.


The color_id


MySQL - Find rows matching all rows from joined table AND string from other tables
by Blunc in Databases

this is a follow up from http://stackoverflow.com/questions/1242223/mysql-find-rows-matching-all-rows-from-joined-table


Thanks to this site the query runs perfectly.


But now i had to extend the query for a search for artist and track. This has lead me to the following query:


SELECT DISTINCT`t`.`id`
FROM `trackwords` AS `tw`
INNER JOIN `wordlis

No rows returned when calling stored procedure although running code in that very SP returns rows
by Dahak in Databases

Whenever I call a stored procedure that contains more than a single select statement I get no rows in the resultset although running the same code outside the SP returns the expected result. This has started happening by the time a database backup from a production environment was installed on the development server.


The example below returns no rows when run in Enterprise Manager 2


Performance consideration: Spread rows in multiple tables vs concentrate all rows in one table
by Thomas Gueze in Databases
Performance consideration: Spread rows in multiple tables vs concentrate all rows in one table.

Hi.


I need to log information about about every step that goes on in the application in an SQL DB.
There are certain tables, I want the log should be related to:
Product - should log when a product has been created changed etc.
Order - same as above
Shipping - sam


How can I extract the rows from a large data set by common IDs and take the means of these rows and make a column having these IDs
by Kiltec in Programming Languages

I know it is a very silly question but I could not sort it out that is why asking...
How can I extract the rows from a large data set by common IDs and take the means of these rows and make a column having these IDs as rownames.
e.g.


IDs Var2
Ae4 2
Ae4 4
Ae4 6
Bc3 3
Bc3 5
Ad2 8
Ad2 7
OutPut
Var(x)
Ae4 4<

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