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How to retrieve the current value of an oracle sequence without increment it?
...
SELECT last_number
FROM all_sequences
WHERE sequence_owner = '<sequence owner>'
AND sequence_name = '<sequence_name>';
You can get a variety of sequence metadata from user_sequences, all_sequences and dba_...
How do I check to see if a value is an integer in MySQL?
...e REGEXP operator, matching the string to a regular expression. Simply do
select field from table where field REGEXP '^-?[0-9]+$';
this is reasonably fast. If your field is numeric, just test for
ceil(field) = field
instead.
...
How do I get bit-by-bit data from an integer value in C?
...s:
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char** argv)
{
unsigned
input = 0b0111u,
n_bits = 4u,
*bits = (unsigned*)malloc(sizeof(unsigned) * n_bits),
bit = 0;
for(bit = 0; bit < n_bits; ++bit)
bits[bit] = (input >...
MySQL Great Circle Distance (Haversine formula)
...ults. To search by kilometers instead of miles, replace 3959 with 6371.
SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) )
* cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin(radians(lat)) ) ) AS distance
FROM markers
HAVING distance < 25
ORDER BY distance ...
SQL query return data from multiple tables
...rows affected (0.00 sec)
Records: 5 Duplicates: 0 Warnings: 0
mysql> select * from colors;
+----+-------+----------+
| id | color | paint |
+----+-------+----------+
| 1 | Red | Metallic |
| 2 | Green | Gloss |
| 3 | Blue | Metallic |
| 4 | White | Gloss |
| 5 | Black | Gloss ...
Linq: What is the difference between Select and Where
The Select and Where methods are available in Linq. What should every developer know about these two methods? For example: when to use one over the other, any advantages of using one over the other, etc.
...
MySQL: Fastest way to count number of rows
...s.
The solution is SQL_CALC_FOUND_ROWS. This is usually used when you are selecting rows but still need to know the total row count (for example, for paging).
When you select data rows, just append the SQL_CALC_FOUND_ROWS keyword after SELECT:
SELECT SQL_CALC_FOUND_ROWS [needed fields or *] FROM t...
Simplest way to do a recursive self-join?
...
WITH q AS
(
SELECT *
FROM mytable
WHERE ParentID IS NULL -- this condition defines the ultimate ancestors in your chain, change it as appropriate
UNION ALL
SELECT m.*
FROM mytable m
...
SQL - using alias in Group By
... following order:
FROM clause
WHERE clause
GROUP BY clause
HAVING clause
SELECT clause
ORDER BY clause
For most relational database systems, this order explains which names (columns or aliases) are valid because they must have been introduced in a previous step.
So in Oracle and SQL Server, you...
SSH to Elastic Beanstalk instance
... region.
Configure Security Group
In the AWS console, open the EC2 tab.
Select the relevant region and click on Security Group.
You should have an elasticbeanstalk-default security group if you have launched an Elastic Beanstalk instance in that region.
Edit the security group to add a rule for S...