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What is the difference between SQL, PL-SQL and T-SQL?
...ry language to operate on sets.
It is more or less standardized, and used by almost all relational database management systems: SQL Server, Oracle, MySQL, PostgreSQL, DB2, Informix, etc.
PL/SQL is a proprietary procedural language used by Oracle
PL/pgSQL is a procedural language used by PostgreSQL
...
What is the difference between memoization and dynamic programming?
...gramming problem using tabulation you solve the problem "bottom up", i.e., by solving all related sub-problems first, typically by filling up an n-dimensional table. Based on the results in the table, the solution to the "top" / original problem is then computed.
If you use memoization to solve the...
Why aren't pointers initialized with NULL by default?
...sume that the compiler initialized any variable not explicitly initialized by the developer. Then we run into situations where initializing the variable was non trivial and the reason the developer did not do it at the declaration point was he/she needed to perform some operation and then assign.
S...
Get top 1 row of each group
...
;WITH cte AS
(
SELECT *,
ROW_NUMBER() OVER (PARTITION BY DocumentID ORDER BY DateCreated DESC) AS rn
FROM DocumentStatusLogs
)
SELECT *
FROM cte
WHERE rn = 1
If you expect 2 entries per day, then this will arbitrarily pick one. To get both entries for a day, use DENSE_RANK ...
In jQuery, how do I select an element by its name attribute?
...radio that way jQuery can take advantage of the performance boost provided by the native DOM querySelectorAll() method.
– Adam
Oct 28 '12 at 18:01
...
Number of rows affected by an UPDATE in PL/SQL
...I update some rows. Is there a way to find out how many rows were affected by the UPDATE? When executing the query manually it tells me how many rows were affected, I want to get that number in PL/SQL.
...
Get specific object by id from array of objects in AngularJS
...ate over the array. Obviously if you are sure that the results are ordered by id you can do a binary search
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WHERE vs HAVING
...ber") after HAVING and not WHERE in MySQL?
WHERE is applied before GROUP BY, HAVING is applied after (and can filter on aggregates).
In general, you can reference aliases in neither of these clauses, but MySQL allows referencing SELECT level aliases in GROUP BY, ORDER BY and HAVING.
And are t...
What is the difference between Set and List?
...ere in the
list each element is inserted. The
user can access elements by their
integer index (position in the list),
and search for elements in the list.
Set<E>:
A collection that contains no
duplicate elements. More formally,
sets contain no pair of elements e1
and e2 suc...
When should I use Write-Error vs. Throw? Terminating vs. non-terminating errors
...ror should be used if you want to inform the user of a non-critical error. By default all it does is print an error message in red text on the console. It does not stop a pipeline or a loop from continuing. Throw on the other hand produces what is called a terminating error. If you use throw, the pi...