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SQL Update with row_number()
... attempt failed primarily because you named the CTE same as the underlying table and made the CTE look as if it was a recursive CTE, because it essentially referenced itself. A recursive CTE must have a specific structure which requires the use of the UNION ALL set operator.
Instead, you could just...
How to get the top 10 values in postgresql?
... *,
rank() over (order by some_value_column desc) as my_rank
from mytable) subquery
where my_rank <= 10
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Why is a “GRANT USAGE” created the first time I grant a user privileges?
...e MySQL server, hence USAGE. It corresponds to a row in the `mysql`.`user` table with no privileges set.
The IDENTIFIED BY clause indicates that a password is set for that user. How do we know a user is who they say they are? They identify themselves by sending the correct password for their accoun...
What is the best way to stop people hacking the PHP-based highscore table of a Flash game
...both these conditions are true, it writes the high score to the high score table and returns a signed "success" message to the client. It also removes the salt value from the pending query list.
Please keep in mind that the security of any of the above techniques is compromised if the shared secr...
Detect if value is number in MySQL
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This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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Advantages and disadvantages of GUID / UUID database keys
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@Matt Sheppard:
Say you have a table of customers. Surely you don't want a customer to exist in the table more than once, or lots of confusion will happen throughout your sales and logistics departments (especially if the multiple rows about the customer c...
How can I get around MySQL Errcode 13 with SELECT INTO OUTFILE?
I am trying to dump the contents of a table to a csv file using a MySQL SELECT INTO OUTFILE statement. If I do:
13 Answers...
Postgresql query between date ranges
...= 2
This involves calculating the conditions for every single row in the table (a scan) and not using index to find the range of rows that will match (a range-seek).
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JPA: what is the proper pattern for iterating over large result sets?
Let's say I have a table with millions of rows. Using JPA, what's the proper way to iterate over a query against that table, such that I don't have all an in-memory List with millions of objects?
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Best Practices: Salting & peppering passwords?
...n order for it to be considered secure. Additionally, it has to be implementable in a maintainable way. The most secure system that can't be maintained is considered insecure (because if any part of that security breaks down, the entire system falls apart).
And peppers fit neither the provable or t...