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MySQL select one column DISTINCT, with corresponding other columns
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try this query
SELECT ID, FirstName, LastName FROM table GROUP BY(FirstName)
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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
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Since dplyr 0.8 group_by gained the .drop argument that does just what you asked for:
df = data.frame(a=rep(1:3,4), b=rep(1:2,6))
df$b = factor(df$b, levels=1:3)
df %>%
group_by(b, .drop=FALSE) %>%
summarise(count_a=length(a))
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MySQL and GROUP_CONCAT() maximum length
I'm using GROUP_CONCAT() in a MySQL query to convert multiple rows into a single string.
However, the maximum length of the result of this function is 1024 characters.
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Bootstrap: align input with button
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In Twitter Bootstrap 4, inputs and buttons can be aligned using the input-group-prepend and input-group-append classes (see https://getbootstrap.com/docs/4.0/components/input-group/#button-addons)
Group button on the left side (prepend)
<div class="input-group mb-3">
<div class="input-...
GROUP BY with MAX(DATE) [duplicate]
...You cannot include non-aggregated columns in your result set which are not grouped. If a train has only one destination, then just add the destination column to your group by clause, otherwise you need to rethink your query.
Try:
SELECT t.Train, t.Dest, r.MaxTime
FROM (
SELECT Train, MAX(Tim...
How to access pandas groupby dataframe by key
How do I access the corresponding groupby dataframe in a groupby object by the key?
5 Answers
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jQuery Validate - require at least one field in a group to be filled
...ms. On one form, I need to ensure that the user fills in at least one of a group of fields. I think I've got a pretty good solution, and wanted to share it. Please suggest any improvements you can think of.
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How can we match a^n b^n with Java regex?
...) {
foreach ($tests as $test) {
$isMatch = preg_match($r, $test, $groups);
$groupsJoined = join('|', $groups);
print("$test $isMatch $groupsJoined\n");
}
}
$tests = array('aaa', 'aaab', 'aaaxb', 'xaaab', 'b', 'abbb');
$r1 = '/^a+(?=b+)/';
# └────┘
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Group query results by month and year in postgresql
...act(year from date) as yyyy,
sum("Sales") as "Sales"
from yourtable
group by 1,2
At the request of Radu, I will explain that query:
to_char(date,'Mon') as mon, : converts the "date" attribute into the defined format of the short form of month.
extract(year from date) as yyyy : Postgresql'...
SQL select only rows with max value on a column [duplicate]
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At first glance...
All you need is a GROUP BY clause with the MAX aggregate function:
SELECT id, MAX(rev)
FROM YourTable
GROUP BY id
It's never that simple, is it?
I just noticed you need the content column as well.
This is a very common question in SQL: fi...