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What columns generally make good indexes?
...earching the results speedily from tables. So it is most important step to select which columns to be indexed. There are two major places where we can consider indexing: columns referenced in the WHERE clause and columns used in JOIN clauses. In short, such columns should be indexed against which yo...
Is it possible to select the last n items with nth-child?
Using a standard list, I'm trying to select the last 2 list items. I've various permutations of An+B but nothing seems to select the last 2:
...
MySQL COUNT DISTINCT
...
Select
Count(Distinct user_id) As countUsers
, Count(site_id) As countVisits
, site_id As site
From cp_visits
Where ts >= DATE_SUB(NOW(), INTERVAL 1 DAY)
Group By site_id
...
The maximum recursion 100 has been exhausted before statement completion
...@EntDt = '12/31/2009';
declare @dcnt int;
;with DateList as
(
select @STARTDATE DateValue
union all
select DateValue + 1 from DateList
where DateValue + 1 < convert(VARCHAR(15),@EntDt,101)
)
select count(*) as DayCnt from (
select DateValue,...
How can I change the file type association of an existing file in WebStorm?
...t patterns by which a file gets associated as some type or other.
If you select the patterns for a file type you have wrongly selected (in your case Text type) you can remove the filename pattern with which was created to associate you file's filename as a wrong type.
Then click Apply > OK
...
Can I have multiple Xcode versions installed?
... explicitly specify it at install time. Also, you will generally want to unselect all features besides the xcode core tools, because the others don't let you change the install directory.
– Paul Du Bois
Jul 3 '11 at 3:30
...
Selecting pandas column by location
...ed in future versions. See pandas.pydata.org/pandas-docs/dev/… on how to select by position using iloc/iat.
– Wouter Overmeire
Apr 12 '13 at 10:04
1
...
Transaction isolation levels relation with locks on table
... writes data and commit/rollback (depending on results). B just executes a SELECT statement to read data. C reads and updates data. All these process work on the same table T.
READ UNCOMMITTED - no lock on the table. You can read data in the table while writing on it. This means A writes data (unc...
LINQ query on a DataTable
...w in myDataTable.AsEnumerable()
where myRow.Field<int>("RowNo") == 1
select myRow;
And as @Keith says, you'll need to add a reference to System.Data.DataSetExtensions
AsEnumerable() returns IEnumerable<DataRow>. If you need to convert IEnumerable<DataRow> to a DataTable, use the...
How to take all but the last element in a sequence using LINQ?
...eq = Enumerable.Range(1, 10);
Console.WriteLine(string.Join(", ", Seq.Select(x => x.ToString()).ToArray()));
Console.WriteLine(string.Join(", ", Seq.TakeAllButLast().Select(x => x.ToString()).ToArray()));
}
Or as a generalized solution discarding the last n items (using a queue like...