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MySQL “Group By” and “Order By”
I want to be able to select a bunch of rows from a table of e-mails and group them by the from sender. My query looks like this:
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How to think in data stores instead of databases?
...trained my mind to think 100% in object relationships that map directly to table structures, and now it's hard to see anything differently. I can understand some of the benefits of Google Datastore (e.g. performance and the ability to distribute data), but some good database functionality is sacrif...
SQL join: selecting the last records in a one-to-many relationship
Suppose I have a table of customers and a table of purchases. Each purchase belongs to one customer. I want to get a list of all customers along with their last purchase in one SELECT statement. What is the best practice? Any advice on building indexes?
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How to place div side by side
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Using CSS display property - which can be used to make divs act like a table:
<div style="width: 100%; display: table;">
<div style="display: table-row">
<div style="width: 600px; display: table-cell;"> Left </div>
<div style="display: table-ce...
Stored procedure slow when called from web, fast from Management Studio
... change:
ALTER PROCEDURE [dbo].[sproc]
@param1 int,
AS
SELECT * FROM Table WHERE ID = @param1
to:
ALTER PROCEDURE [dbo].[sproc]
@param1 int,
AS
DECLARE @param1a int
SET @param1a = @param1
SELECT * FROM Table WHERE ID = @param1a
Seems strange, but it fixed my problem.
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How to load a tsv file into a Pandas DataFrame?
...od - it was very slow and failed indexing at the end. Instead, i used read_table(), which worked much faster and without the extra param.
– Yurik
Aug 15 '14 at 9:56
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SQL Server Text type vs. varchar data type [closed]
...NTEXT. You'll need to enable large value types out of row for them with sp_tableoption if you want them to be always stored out of row.
As mentioned above and here, TEXT is going to be deprecated in future releases:
The text in row option will be removed in a future version of SQL Server. Avoid usi...
How do I view the full content of a text or varchar(MAX) column in SQL Server 2008 Management Studio
... this live SQL Server 2008 (build 10.0.1600) database, there's an Events table, which contains a text column named Details . (Yes, I realize this should actually be a varchar(MAX) column, but whoever set this database up did not do it that way.)
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Using DISTINCT and COUNT together in a MySQL Query
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use
SELECT COUNT(DISTINCT productId) from table_name WHERE keyword='$keyword'
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efficient way to implement paging
...mehow direct paging in the SQL engine.
Giving you an example, I have a db table called mtcity and I wrote the following query (work as well with linq to entities):
using (DataClasses1DataContext c = new DataClasses1DataContext())
{
var query = (from MtCity2 c1 in c.MtCity2s
sel...