大约有 44,000 项符合查询结果（耗时：0.0324秒） [XML]
Using IQueryable with Linq
...ram. Your program then filters the data. In essence, the database does a SELECT * FROM Products, and returns EVERY product to you.
With the right IQueryable<T> provider, on the other hand, you can do:
IQueryable<Product> products = myORM.GetQueryableProducts();
var productsOver25 =...
MySQL Results as comma separated list
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You can use GROUP_CONCAT to perform that, e.g. something like
SELECT p.id, p.name, GROUP_CONCAT(s.name) AS site_list
FROM sites s
INNER JOIN publications p ON(s.id = p.site_id)
GROUP BY p.id, p.name;
share
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postgres default timezone
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Choose a timezone from:
SELECT * FROM pg_timezone_names;
And set as below given example:
ALTER DATABASE postgres SET timezone TO 'Europe/Berlin';
Use your DB name in place of postgres in above statement.
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Linq: adding conditions to the where clause conditionally
... && u.Age > 18
&& u.Height > strHeightinFeet
select u;
if (useAge)
query = query.Where(u => u.Age > age);
if (useHeight)
query = query.Where(u => u.Height > strHeightinFeet);
// Build the results at the end
var results = query.Select(u => new DTO...
Replacement for “rename” in dplyr
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The next version of dplyr will support an improved version of select that also incorporates renaming:
> mtcars2 <- select( mtcars, disp2 = disp )
> head( mtcars2 )
disp2
Mazda RX4 160
Mazda RX4 Wag 160
Datsun 710 108
Hornet 4 Drive 258
H...
How do I turn off Oracle password expiration?
...rtain user profile in Oracle first check which profile the user is using:
select profile from DBA_USERS where username = '<username>';
Then you can change the limit to never expire using:
alter profile <profile_name> limit password_life_time UNLIMITED;
If you want to previously che...
Is there a CSS parent selector?
How do I select the <li> element that is a direct parent of the anchor element?
33 Answers
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MVC3 DropDownListFor - a simple example?
...uirements. Now, however, how is MVC FW supposed to map the value that is selected on this drop-down back into the simple string property on my view model?
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SQL error “ORA-01722: invalid number”
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Well it also can be :
SELECT t.col1, t.col2, ('test' + t.col3) as test_col3
FROM table t;
where for concatenation in oracle is used the operator || not +.
In this case you get : ORA-01722: invalid number ...
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Eclipse git checkout (aka, revert)
...ing" view, right click the deleted file in the "Unstaged Changes" list and select "Replace with HEAD Revision"
– Vlasta Dolejs
Sep 5 '17 at 8:03
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