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Efficiently convert rows to columns in sql server
...Code, LastName, AccountNumber
from
(
select value, columnname
from yourtable
) d
pivot
(
max(value)
for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber)
) piv;
See Demo.
Pivot with unknown number of columnnames
If you have an unknown number of columnnames that you w...
sqlite alter table add MULTIPLE columns in a single statement
Is it possible to alter table add MULTIPLE columns in a single statement in sqlite?
The following would not work.
4 Answers...
MySQL ON vs USING?
...fferences are noteworthy:
ON is the more general of the two. One can join tables ON a column, a set of columns and even a condition. For example:
SELECT * FROM world.City JOIN world.Country ON (City.CountryCode = Country.Code) WHERE ...
USING is useful when both tables share a column of the exac...
How do I find which transaction is causing a “Waiting for table metadata lock” state?
I am trying to perform some DDL on a table and SHOW PROCESSLIST results in a " Waiting for table metadata lock " message.
...
Having both a Created and Last Updated timestamp columns in MySQL 4.0
I have the following table schema;
11 Answers
11
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UITableViewCell, show delete button on swipe
How do I get the delete button to show when swiping on a UITableViewCell ? The event is never raised and the delete button never appears.
...
Simple way to convert datarow array to datatable
I want to convert a DataRow array into DataTable ... What is the simplest way to do this?
14 Answers
...
How To: Best way to draw table in console app (C#)
... of data changing in very fast intervals.
I want to display that data as a table in console app. f.ex:
12 Answers
...
When increasing the size of VARCHAR column on a large table could there be any problems?
...er 2008 and I need to make a VARCHAR field bigger, from (200 to 1200) on a table with about 500k rows. What I need to know is if there are any issues I have not considered.
...
When and why are database joins expensive?
...nality when (if) they set up indexes.
It is important to understand that table scans (examination of every row in a table in the course of producing a join) are rare in practice. A query optimiser will choose a table scan only when one or more of the following holds.
There are fewer than 200 row...