大约有 47,000 项符合查询结果（耗时：0.0402秒） [XML]
INSERT IF NOT EXISTS ELSE UPDATE?
...ike:
insert or replace into Book (ID, Name, TypeID, Level, Seen) values
((select ID from Book where Name = "SearchName"), "SearchName", ...);
Note that any field not in the insert list will be set to NULL if the row already exists in the table. This is why there's a subselect for the ID column: I...
How to get distinct values for non-key column fields in Laravel?
...lder you can do it this way:
$users = DB::table('users')
->select('id','name', 'email')
->groupBy('name')
->get();
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What is the dual table in Oracle?
...
It's a sort of dummy table with a single record used for selecting when you're not actually interested in the data, but instead want the results of some system function in a select statement:
e.g. select sysdate from dual;
See http://www.adp-gmbh.ch/ora/misc/dual.html
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Find the number of columns in a table
...
SELECT COUNT(*)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_catalog = 'database_name' -- the database
AND table_name = 'table_name'
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How to get the first and last date of the current year?
...
SELECT
DATEADD(yy, DATEDIFF(yy, 0, GETDATE()), 0) AS StartOfYear,
DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, -1) AS EndOfYear
The above query gives a datetime value for midnight at the beginning of December 31. This ...
How to use a class from one C# project with another C# project
...Explorer' tree, expand the P2 project and then right-click the project and select 'Add Reference' from the menu.
On the 'Add Reference' dialog, select the 'Projects' tab and select your P1 project.
If you are using namespaces then you will need to import the namespaces for your P1 types by adding ...
ORDER BY the IN value list
... (introduced in PostgreSQL 8.2) VALUES (), ().
Syntax will be like this:
select c.*
from comments c
join (
values
(1,1),
(3,2),
(2,3),
(4,4)
) as x (id, ordering) on c.id = x.id
order by x.ordering
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How do I compare two files using Eclipse? Is there any option provided by Eclipse?
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To compare two files in Eclipse, first select them in the Project Explorer / Package Explorer / Navigator with control-click. Now right-click on one of the files, and the following context menu will appear. Select Compare With / Each Other.
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Get selected element's outer HTML
I'm trying to get the HTML of a selected object with jQuery. I am aware of the .html() function; the issue is that I need the HTML including the selected object (a table row in this case, where .html() only returns the cells inside the row).
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How to insert a line break in a SQL Server VARCHAR/NVARCHAR string
...NVARCHAR(100)
SET @text = 'This is line 1.' + CHAR(13) + 'This is line 2.'
SELECT @text
This prints out the following:
This is line 1.
This is line 2.
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