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Select multiple columns in data.table by their numeric indices
How can we select multiple columns using a vector of their numeric indices (position) in data.table ?
5 Answers
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Grouped LIMIT in PostgreSQL: show the first N rows for each group?
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New solution (PostgreSQL 8.4)
SELECT
*
FROM (
SELECT
ROW_NUMBER() OVER (PARTITION BY section_id ORDER BY name) AS r,
t.*
FROM
xxx t) x
WHERE
x.r <= 2;
sha...
How to group time by hour or by 10 minutes
...time intervals. (There is no collision between years.)
Including it in the SELECT statement will give your output a column with pretty output truncated at the level you specify.
'2000' is an "anchor date" around which SQL will perform the date math. Jereonh discovered below that you encounter an in...
PostgreSQL - max number of parameters in “IN” clause?
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explain select * from test where id in (values (1), (2));
QUERY PLAN
Seq Scan on test (cost=0.00..1.38 rows=2 width=208)
Filter: (id = ANY ('{1,2}'::bigint[]))
But if try 2nd query:
explain select * from test where id = an...
LINQ to SQL - Left Outer Join with multiple join conditions
...g.Where(f => f.otherid == 17).DefaultIfEmpty()
where p.companyid == 100
select f.value
Or you could use a subquery:
from p in context.Periods
join f in context.Facts on p.id equals f.periodid into fg
from fgi in (from f in fg
where f.otherid == 17
select f).DefaultIfE...
How to count instances of character in SQL Column
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In SQL Server:
SELECT LEN(REPLACE(myColumn, 'N', ''))
FROM ...
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MySQL Query GROUP BY day / month / year
... for added clarity in some cases such as where records span several years. SELECT COUNT(event_id), DATE_FORMAT(event_start, '%Y/%m')
– Ric
Apr 4 '13 at 10:25
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How to export query result to csv in Oracle SQL Developer?
...worksheet toolbar)
That's it.
Method 2
Run a query
Right click and select unload.
Update. In Sql Developer Version 3.0.04 unload has been changed to export
Thanks to Janis Peisenieks for pointing this out
Revised screen shot for SQL Developer Version 3.0.04
From the format drop down...
Why shouldn't I use mysql_* functions in PHP?
... 5.5 and above)
$link = mysql_connect('localhost', 'user', 'pass');
mysql_select_db('testdb', $link);
mysql_set_charset('UTF-8', $link);
With PDO: All you need to do is create a new PDO object. The constructor accepts parameters for specifying the database source PDO's constructor mostly takes fo...
Selecting only first-level elements in jquery
How can I select the link elements of only the parent <ul> from a list like this?
10 Answers
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