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What are the lesser known but useful data structures?
...s are painfully expensive, given that a pointer is generally longer than a char, which is a shame. They're only suitable for certain data-sets.
– Joe
Jan 29 '10 at 12:06
18
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SQL Server: Difference between PARTITION BY and GROUP BY
...y're used in different places. group by modifies the entire query, like:
select customerId, count(*) as orderCount
from Orders
group by customerId
But partition by just works on a window function, like row_number:
select row_number() over (partition by customerId order by orderId)
as OrderN...
How to generate a random int in C?
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If you need secure random characters or integers:
As addressed in how to safely generate random numbers in various programming languages, you'll want to do one of the following:
Use libsodium's randombytes API
Re-implement what you need from libsod...
MySQL Select Query - Get only first 10 characters of a value
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Using the below line
SELECT LEFT(subject , 10) FROM tbl
MySQL Doc.
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IntelliJ IDEA: Move line?
... class
Click on relevant class (Red color field) and press,
Alt + Enter
Select valid class as per requirement
(8) Hierarchy of method calls
Select specific method and press,
Ctrl + Alt + H
(9) Comment In Code
Single Line : Select specific line and press,
Ctrl + /
Multiple Line : Select...
Add disabled attribute to input element using Javascript
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Working code from my sources:
HTML WORLD
<select name="select_from" disabled>...</select>
JS WORLD
var from = jQuery('select[name=select_from]');
//add disabled
from.attr('disabled', 'disabled');
//remove it
from.removeAttr("disabled");
...
What is the relative performance difference of if/else versus switch statement in Java?
... just ints. From the Java Tutorials: "A switch works with the byte, short, char, and int primitive data types. It also works with enumerated types (discussed in Enum Types), the String class, and a few special classes that wrap certain primitive types: Character, Byte, Short, and Integer (discussed ...
Join between tables in two different databases?
...
Yes, assuming the account has appropriate permissions you can use:
SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;
You just need to prefix the table reference with the name of the database it resides in.
...
Postgres DB Size Command
..."pg_datbase" system table. Just apply the function to the names, as below.
select t1.datname AS db_name,
pg_size_pretty(pg_database_size(t1.datname)) as db_size
from pg_database t1
order by pg_database_size(t1.datname) desc;
If you intend the output to be consumed by a machine instead of a...
Select Multiple Fields from List in Linq
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Anonymous types allow you to select arbitrary fields into data structures that are strongly typed later on in your code:
var cats = listObject
.Select(i => new { i.category_id, i.category_name })
.Distinct()
.OrderByDescending(i => i.c...