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Select distinct using linq [duplicate]
...
myList.GroupBy(test => test.id)
.Select(grp => grp.First());
Edit: as getting this IEnumerable<> into a List<> seems to be a mystery to many people, you can simply write:
var result = myList.GroupBy(test => test.id)
.S...
Where's my JSON data in my incoming Django request?
...'/event/save-json/',
type: 'POST',
contentType: 'application/json; charset=utf-8',
data: $.toJSON(myEvent),
dataType: 'text',
success: function(result) {
alert(result.Result);
}
});
Django:
def save_events_json(request):
if request.is_ajax():
if request...
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: 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...
Selecting only numeric columns from a data frame
...traightforward, and robust to use on database-back-ended tibbles:
dplyr::select_if(x, is.numeric)
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Selecting element by data attribute
Is there an easy and straight-forward method to select elements based on their data attribute? For example, select all anchors that has data attribute named customerID which has value of 22 .
...
How to Join to first row
...
SELECT Orders.OrderNumber, LineItems.Quantity, LineItems.Description
FROM Orders
JOIN LineItems
ON LineItems.LineItemGUID =
(
SELECT TOP 1 LineItemGUID
FROM LineItems
W...
Check if value exists in Postgres array
...
Simpler with the ANY construct:
SELECT value_variable = ANY ('{1,2,3}'::int[])
The right operand of ANY (between parentheses) can either be a set (result of a subquery, for instance) or an array. There are several ways to use it:
SQLAlchemy: how to filt...
Only one expression can be specified in the select list when the subquery is not introduced with EXI
...column on the other side of the IN. So the query needs to be of the form:
SELECT * From ThisTable WHERE ThisColumn IN (SELECT ThatColumn FROM ThatTable)
You also want to add sorting so you can select just from the top rows, but you don't need to return the COUNT as a column in order to do your so...
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_...