大约有 44,000 项符合查询结果（耗时：0.0320秒） [XML]
Which SQL query is faster? Filter on Join criteria or Where clause?
...INNER JOIN with a LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = a.ID
AND a.ID = 1
LEFT JOIN
TableB b
ON x.TableBID = b.ID
or this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x...
Linq Syntax - Selecting multiple columns
...
.Where(x => x.EMAIL == givenInfo || x.USER_NAME == givenInfo)
.Select(x => new { x.EMAIL, x.ID });
AFAIK, the declarative LINQ syntax is converted to a method call chain similar to this when it is compiled.
UPDATE
If you want the entire object, then you just have to omit the call ...
How can I tell when a MySQL table was last updated?
...e information_schema database to tell you when another table was updated:
SELECT UPDATE_TIME
FROM information_schema.tables
WHERE TABLE_SCHEMA = 'dbname'
AND TABLE_NAME = 'tabname'
This does of course mean opening a connection to the database.
An alternative option would be to "touch" a ...
How many GCC optimization levels are there?
...?
integral_argument also thinly wraps atoi and rejects the argument if any character is not a digit. So negative values fail gracefully.
Back to opts.c:default_options_optimization, we see the line:
if ((unsigned int) opts->x_optimize > 255)
opts->x_optimize = 255;
so that the optimizati...
What are the most useful Intellij IDEA keyboard shortcuts? [closed]
...
These are some of my most used keyboard short cuts
Syntax aware selection in the editor selects a word at the caret and then selects expanding areas of the source code. For example, it may select a method name, then the expression that calls this method, then the whole statement, then the...
CSS Input with width: 100% goes outside parent's bound
...il" class="login-field">
<label for="email" style="-moz-user-select: none;-webkit-user-select: none;" onselectstart="return false;">E-mail address</label>
<span><input name="email" id="email" type="text" /></span>
</div>
<div clas...
How to construct a REST API that takes an array of id's for the resources
...rRepository.GetAllUsersByIds(userIds);
var collection = users.Select(user => new { id = user.Id, fullname = user.FirstName +" "+ user.LastName });
var result = new { users = collection };
return this.Jsonp(result);
}
public IQueryable<User&...
When to use single quotes, double quotes, and backticks in MySQL
...ng query will produce different results (or errors) depending on SQL mode:
SELECT "column" FROM table WHERE foo = "bar"
ANSI_QUOTES disabled
The query will select the string literal "column" where column foo is equal to string "bar"
ANSI_QUOTES enabled
The query will select the column column where ...
How can I check whether a option already exist in select by JQuery
How can I check whether a option already exist in select by JQuery?
8 Answers
8
...
Is there a __CLASS__ macro in C++?
...
That's better. As for knowing the class, defining char array sounds better than postponing it till runtime.
– Michael Krelin - hacker
Nov 3 '09 at 12:21
5
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