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What's the difference between comma separated joins and join on syntax in MySQL? [duplicate]
...LL
)
Following query will give me all columns and rows from both tables
SELECT
*
FROM table1, table2
Following query will give me columns from first table with table alias called 'table2'
SELECT
*
FROM table1 table2
If you mistakenly forget comma in comma-separated join, second table...
How to generate sample XML documents from their DTD or XSD?
... yes, this is the easiest way. Open XSD, switch to XML Schema Explorer, select the root node, right click and choose "Generate Sample Xml".
– balint
Jul 18 '09 at 16:58
3
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Binding a WPF ComboBox to a custom list
I have a ComboBox that doesn't seem to update the SelectedItem/SelectedValue.
4 Answers
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How to check if an element does NOT have a specific class?
...t one for the case in the question, but just as a reference if you need to select elements that don't have a certain class, you can use the not selector:
// select all divs that don't have class test
$( 'div' ).not( ".test" );
$( 'div:not(.test)' ); // <-- alternative
...
When and why are database joins expensive?
...s back to mitigating the size of the working set. Joins involving properly selected keys with correctly set up indexes are cheap, not expensive, because they allow significant pruning of the result before the rows are materialised.
Materialising the result involves bulk disk reads which are the mo...
Memcached下一站：HandlerSocket！ - 更多技术 - 清泛网 - 专注C/C++及内核技术
...没有实际运行SQL，所以Binlog记录的是Row格式。
SQL原型：SELECT id, a, b FROM test.t WHERE id = 1 LIMIT 1
shell> telnet localhost 9999
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
P 1 test t PRIMARY id,a,b
0 1
1 = ...
When should I use semicolons in SQL Server?
...llowing two queries (copied from this post):
BEGIN TRY
BEGIN TRAN
SELECT 1/0 AS CauseAnException
COMMIT
END TRY
BEGIN CATCH
SELECT ERROR_MESSAGE()
THROW
END CATCH
BEGIN TRY
BEGIN TRAN
SELECT 1/0 AS CauseAnException;
COMMIT
END TRY
BEGIN CATCH
SELECT ERROR_MES...
USB Debugging option greyed out
...of this post.
When you connect your phone to your PC, using the USB cable, select the mode as PC Software.
Now you should be able to enable USB Debugging.
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DataTrigger where value is NOT null?
...
I'm using this to only enable a button if a listview item is selected (ie not null):
<Style TargetType="{x:Type Button}">
<Setter Property="IsEnabled" Value="True"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=lvMyList, Path=Selecte...
Laravel Eloquent: Ordering results of all()
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Note, you can do:
$results = Project::select('name')->orderBy('name')->get();
This generate a query like:
"SELECT name FROM proyect ORDER BY 'name' ASC"
In some apps when the DB is not optimized and the query is more complex, and you need prevent gener...