大约有 48,000 项符合查询结果（耗时：0.0328秒） [XML]
COUNT DISTINCT with CONDITIONS
...
You can try this:
select
count(distinct tag) as tag_count,
count(distinct (case when entryId > 0 then tag end)) as positive_tag_count
from
your_table_name;
The first count(distinct...) is easy.
The second one, looks somewhat complex...
Error 1046 No database Selected, how to resolve?
...ation.
If you're trying to do this via MySQL Workbench...
...you need to select the appropriate database/catalog in the drop down menu found above the :Object Browser: tab. You can specify the default schema/database/catalog for the connection - click the "Manage Connections" options under the SQL...
IntelliJ does not show 'Class' when we right click and select 'New'
... and must have something wrong because when we right click on a directory, select New and then get the context menu, Java based options are not shown. Currently get things like File, some HTML options, XML options.
...
Convert varchar to uniqueidentifier in SQL Server
...
DECLARE @uuid VARCHAR(50)
SET @uuid = 'a89b1acd95016ae6b9c8aabb07da2010'
SELECT CAST(
SUBSTRING(@uuid, 1, 8) + '-' + SUBSTRING(@uuid, 9, 4) + '-' + SUBSTRING(@uuid, 13, 4) + '-' +
SUBSTRING(@uuid, 17, 4) + '-' + SUBSTRING(@uuid, 21, 12)
AS UNIQUEIDENTIFIER)
...
How do I view the SQL generated by the Entity Framework?
...e query = from x in appEntities
where x.id == 32
select x;
var sql = ((System.Data.Objects.ObjectQuery)query).ToTraceString();
or in EF6:
var sql = ((System.Data.Entity.Core.Objects.ObjectQuery)query)
.ToTraceString();
That will give you the SQL that was g...
The selected run destination is not valid for this action
...ject icon in the left hand panel. 2) In the right hand panel that appears, select Build Settings » all. 3) You'll see the option to change the SDK. Screenshot: img546.imageshack.us/img546/9808/picture3fh.png
– cwd
Dec 16 '11 at 23:12
...
Visual Studio C# statement collapsing
...have to turn off automatic outlining.
Right click in your code window and select (Outlining | Stop Outlining)
Then, select some text, right click and select (Outlining | Hide Selection)
When you turn on automatic outlining again, your custom "Regions" will no longer collapse.
...
Use a list of values to select rows from a pandas dataframe [duplicate]
...andas.pydata.org/pandas-docs/stable/… for more details. A sort after the selection is needed.
– Wouter Overmeire
Aug 18 '14 at 15:16
1
...
Using “like” wildcard in prepared statement
...place("[", "![");
PreparedStatement pstmt = con.prepareStatement(
"SELECT * FROM analysis WHERE notes LIKE ? ESCAPE '!'");
pstmt.setString(1, notes + "%");
or a suffix-match:
pstmt.setString(1, "%" + notes);
or a global match:
pstmt.setString(1, "%" + notes + "%");
...
LINQ Select Distinct with Anonymous Types
...DelegateComparer<T>(equals,null));
}
}
var uniqueItems=students.Select(s=> new {FirstName=s.FirstName, LastName=s.LastName})
.Distinct((a,b) => a.FirstName==b.FirstName, c => c.FirstName.GetHashCode()).ToList();
Sorry for the messed up formatting earlier
...