大约有 40,000 项符合查询结果（耗时：0.0308秒） [XML]
Simplest way to do a recursive self-join?
... m.parentID = q.PersonID
)
SELECT *
FROM q
By adding the ordering condition, you can preserve the tree order:
WITH q AS
(
SELECT m.*, CAST(ROW_NUMBER() OVER (ORDER BY m.PersonId) AS VARCHAR(MAX)) COLLATE Latin1_General_BIN AS bc
FROM mytable m
...
What is the difference between Collection and List in Java?
...5th element in this collection" isn't defined, because there is no defined order.
There are other specialized Collections as well, for example a Set which adds the feature that it will never contain the same element twice.
...
SQlite Getting nearest locations (with latitude and longitude)
... other latitudes, you need to decrease the impact of longitude on the sort order. (Imagine you're close to the north pole... a degree of latitude is still the same as it is anywhere, but a degree of longitude may only be a few feet. This will mean that the sort order is incorrect).
If you are not...
Is there any difference between GROUP BY and DISTINCT
...hat the two operations "happen" at two very different steps in the logical order of operations that are executed in a SELECT statement.
Here are the most important operations:
FROM (including JOIN, APPLY, etc.)
WHERE
GROUP BY (can remove duplicates)
Aggregations
HAVING
Window functions
SELECT
DI...
lodash multi-column sortBy descending
...
As of lodash 3.5.0 you can use sortByOrder (renamed orderBy in v4.3.0):
var data = _.sortByOrder(array_of_objects, ['type','name'], [true, false]);
Since version 3.10.0 you can even use standard semantics for ordering (asc, desc):
var data = _.sortByOrder(ar...
MySQL, update multiple tables with one query
...
Take the case of two tables, Books and Orders. In case, we increase the number of books in a particular order with Order.ID = 1002 in Orders table then we also need to reduce that the total number of books available in our stock by the same number in Books table.
...
Can I concatenate multiple MySQL rows into one field?
...d in their comment, you can also sort the values before imploding it using ORDER BY:
SELECT person_id, GROUP_CONCAT(hobbies ORDER BY hobbies ASC SEPARATOR ', ')
FROM peoples_hobbies
GROUP BY person_id;
As Dag stated in his comment, there is a 1024 byte limit on the result. To solve this, run this q...
How to select unique records by SQL
..., but also the most limited way:
SELECT DISTINCT word, num
FROM dupes
ORDER BY word, num;
/*
word|num|
----|---|
aaa |100|
bbb |200|
bbb |400|
ccc |300|
ddd |400|
*/
Option 2: GROUP BY
Grouping allows you to add aggregated data, like the min(id), max(id), count(*), etc:
SELECT word, num, ...
Accessing items in an collections.OrderedDict by index
...
If its an OrderedDict() you can easily access the elements by indexing by getting the tuples of (key,value) pairs as follows
>>> import collections
>>> d = collections.OrderedDict()
>>> d['foo'] = 'python'
&...
Postgresql GROUP_CONCAT equivalent?
...
Note that the syntax also allows you to specify the order of values in the string (or array, using array_agg) e.g. string_agg(some_column, ',' ORDER BY some_column) or even string_agg(surname || ', ' || forename, '; ' ORDER BY surname, forename)
– IMSoP
...