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Are the days of passing const std::string & as a parameter over?
I heard a recent talk by Herb Sutter who suggested that the reasons to pass std::vector and std::string by const & are largely gone. He suggested that writing a function such as the following is now preferable:
...
Select first row in each GROUP BY group?
...I'd like to select the first row of each set of rows grouped with a GROUP BY .
17 Answers
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LISTAGG in Oracle to return distinct values
...c and later:
select listagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_column
from the_table
) t
If you need more columns, something like this ...
What is the difference between partitioning and bucketing a table in Hive ?
...or department . For a faster query response Hive table can be PARTITIONED BY (country STRING, DEPT STRING). Partitioning tables changes how Hive structures the data storage and Hive will now create subdirectories reflecting the partitioning structure like
.../employees/country=ABC/DEPT=XYZ.
If qu...
Can't get rid of header X-Powered-By:Express
...
In Express >= 3.0.0rc5:
app.disable('x-powered-by');
Here is a simple middleware that removes the header in earlier versions of Express:
app.use(function (req, res, next) {
res.removeHeader("x-powered-by");
next();
});
...
Is Java “pass-by-reference” or “pass-by-value”?
I always thought Java uses pass-by-reference .
81 Answers
81
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Does Javascript pass by reference? [duplicate]
Does Javascript pass by references or pass by values? Here is an example from Javascript: The Good Parts . I am very confused about my parameter for the rectangle function. It is actually undefined , and redefined inside the function. There are no original reference. If I remove it from the func...
MYSQL import data from csv using LOAD DATA INFILE
...INFILE.
LOAD DATA LOCAL INFILE 'abc.csv' INTO TABLE abc
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\r\n'
IGNORE 1 LINES
(col1, col2, col3, col4, col5...);
For MySQL 8.0 users:
Using the LOCAL keyword hold security risks and as of MySQL 8.0 the LOCAL capability is set to Fals...
How to do SELECT COUNT(*) GROUP BY and ORDER BY in Django?
...saction.objects.all().values('actor').annotate(total=Count('actor')).order_by('total')
values() : specifies which columns are going to be used to "group by"
Django docs:
"When a values() clause is used to constrain the columns that are
returned in the result set, the method for evaluating annotati...
How can I group by date time column without taking time into consideration
I have a bunch of product orders and I'm trying to group by the date and sum the quantity for that date. How can I group by the month/day/year without taking the time part into consideration?
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