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How to reset postgres' primary key sequence when it falls out of sync?
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-- Login to psql and run the following
-- What is the result?
SELECT MAX(id) FROM your_table;
-- Then run...
-- This should be higher than the last result.
SELECT nextval('your_table_id_seq');
-- If it's not higher... run this set the sequence last to your highest id.
-- (wise to run...
When to use Common Table Expression (CTE)
...ing well? Can someone give me a simple example of limitations with regular select, derived or temp table queries to make the case of CTE? Any simple examples would be highly appreciated.
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SQL Server SELECT into existing table
I am trying to select some fields from one table and insert them into an existing table from a stored procedure. Here is what I am trying:
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What are best practices that you use when writing Objective-C and Cocoa? [closed]
...aching of responses.
Also of interest, are some good iPhone specific tips from Joseph Mattiello (received in an iPhone mailing list). There are more, but these were the most generally useful I thought (note that a few bits have now been slightly edited from the original to include details offered ...
How do I expire a PHP session after 30 minutes?
.../ Taking now logged in time.
// Ending a session in 30 minutes from the starting time.
$_SESSION['expire'] = $_SESSION['start'] + (30 * 60);
header('Location: http://localhost/somefolder/homepage.php');
} else {
echo "Please enter the username ...
How to write a foreach in SQL Server?
... the lines of a for-each, where I would like to take the Ids of a returned select statement and use each of them.
10 Answer...
What is the best way to detect a mobile device?
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@Andrew but from a developer perspective, those devices must be such a tiny percentage of mobile users that they're not worth catering to. Especially in the U.S.
– Telarian
Feb 7 '19 at 15:00
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Simple way to calculate median with MySQL
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In MariaDB / MySQL:
SELECT AVG(dd.val) as median_val
FROM (
SELECT d.val, @rownum:=@rownum+1 as `row_number`, @total_rows:=@rownum
FROM data d, (SELECT @rownum:=0) r
WHERE d.val is NOT NULL
-- put some where clause here
ORDER BY d.val
) ...
Select first row in each GROUP BY group?
As the title suggests, I'd like to select the first row of each set of rows grouped with a GROUP BY .
17 Answers
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WHERE vs HAVING
Why do you need to place columns you create yourself (for example select 1 as "number" ) after HAVING and not WHERE in MySQL?
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