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Get day of week in SQL Server 2005/2008
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Use DATENAME or DATEPART:
SELECT DATENAME(dw,GETDATE()) -- Friday
SELECT DATEPART(dw,GETDATE()) -- 6
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LINQ - Left Join, Group By, and Count
...into j1
from j2 in j1.DefaultIfEmpty()
group j2 by p.ParentId into grouped
select new { ParentId = grouped.Key, Count = grouped.Count(t=>t.ChildId != null) }
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Can I list-initialize a vector of move-only type?
... rather the underlying elements themselves might be const, which cannot be cast away in a well-formed program.
– underscore_d
Jul 18 '16 at 10:49
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COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
...for all your queries that need to count everything, even for joins, use *
SELECT boss.boss_id, COUNT(subordinate.*)
FROM boss
LEFT JOIN subordinate on subordinate.boss_id = boss.boss_id
GROUP BY boss.id
But don't use COUNT(*) for LEFT joins, as that will return 1 even if the subordinate table doe...
How to copy to clipboard in Vim?
...alent. For X11 systems,
though, they differ. For X11 systems,
* is the selection, and + is the cut buffer (like clipboard).
http://vim.wikia.com/wiki/Accessing_the_system_clipboard
* is probably what you want most of the time, so I use * because it functions as I expect it to in both enviro...
How does one reorder columns in a data frame?
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You can also use the subset function:
data <- subset(data, select=c(3,2,1))
You should better use the [] operator as in the other answers, but it may be useful to know that you can do a subset and a column reorder operation in a single command.
Update:
You can also use the select...
How to automatically generate getters and setters in Android Studio
...ar -> Code -> Generate...
and then using shift or control button, select all the variables you need to add getters and setters
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How to remove all MySQL tables from the command-line without DROP database permissions? [duplicate]
...tatements to execute it:
SET FOREIGN_KEY_CHECKS = 0;
SET @tables = NULL;
SELECT GROUP_CONCAT('`', table_schema, '`.`', table_name, '`') INTO @tables
FROM information_schema.tables
WHERE table_schema = 'database_name'; -- specify DB name here.
SET @tables = CONCAT('DROP TABLE ', @tables);
PRE...
How do I delete a fixed number of rows with sorting in PostgreSQL?
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You could try using the ctid:
DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly,...
How are multi-dimensional arrays formatted in memory?
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The code usually crashes at run-time when array of type int[N][M] is type-casted and then accessed as type int**, for example:
((int**)a1)[1][0] //crash on dereference of a value of type 'int'
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