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How do I check if a number is positive or negative in C#?
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This is the industry standard:
int is_negative(float num)
{
char *p = (char*) malloc(20);
sprintf(p, "%f", num);
return p[0] == '-';
}
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A std::map that keep track of the order of insertion?
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Thats great! Boost even has a member-selector to do the job!
– xtofl
Jul 8 '09 at 14:19
2
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How to declare a variable in a PostgreSQL query
...ows you to return a table of temporary values.
WITH master_user AS (
SELECT
login,
registration_date
FROM users
WHERE ...
)
SELECT *
FROM users
WHERE master_login = (SELECT login
FROM master_user)
AND (SELECT registration_date
FROM ma...
Reference alias (calculated in SELECT) in WHERE clause
The calculated value BalanceDue that is set as a variable in the list of selected columns cannot be used in the WHERE clause.
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jQuery Validate Required Select
I am trying to validate html select element using jQuery Validate plugin. I set "required" rule to true but it always passes validation because zero index is chosed by default. Is there any way to define empty value that is used by required rule?
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How to select a drop-down menu value with Selenium using Python?
I need to select an element from a drop-down menu.
13 Answers
13
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Why can't a text column have a default value in MySQL?
... I try to recreate the table locally with the obvious default (based on a select of unique values for that column) and end up receiving the oh-so-useful BLOB/TEXT column can't have a default value.
Again, not maintaining basic compatability across platforms is unacceptable and is a bug.
How to ...
PostgreSQL - fetch the row which has the Max value for a column
...sted index lookup into lives - on my machine
-- the latter query plan was selected given my memory settings and
-- histogram
SELECT
l1.*
FROM
lives AS l1
INNER JOIN (
SELECT
usr_id,
MAX(time_stamp) AS time_stamp_max
FROM
lives
GROUP BY
usr_id
) AS l2
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Rails 3: Get Random Record
...You can use the following trick on an indexed column (PostgreSQL syntax):
select *
from my_table
where id >= trunc(
random() * (select max(id) from my_table) + 1
)
order by id
limit 1;
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How to copy a row and insert in same table with a autoincrement field in MySQL?
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Use INSERT ... SELECT:
insert into your_table (c1, c2, ...)
select c1, c2, ...
from your_table
where id = 1
where c1, c2, ... are all the columns except id. If you want to explicitly insert with an id of 2 then include that in your INSER...