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Check if table exists and if it doesn't exist, create it in SQL Server 2008
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Something like this
IF NOT EXISTS (SELECT * FROM sys.objects
WHERE object_id = OBJECT_ID(N'[dbo].[YourTable]') AND type in (N'U'))
BEGIN
CREATE TABLE [dbo].[YourTable](
....
....
....
)
END
...
configure: error: C compiler cannot create executables
...'ve installed Xcode 4.3.x, you need to launch it, go into its preferences, select the Downloads tab, and click "Install" next to the Command Line Tools package.
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IN vs OR in the SQL WHERE Clause
...h are nearly instant. When the column is not indexed I got these results:
SELECT COUNT(*) FROM t_inner WHERE val IN (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000);
1 row fetched in 0.0032 (1.2679 seconds)
SELECT COUNT(*) FROM t_inner WHERE val = 1000 OR val = 2000 OR val = 3000 OR val = 40...
MySQL一次主从数据不一致的问题解决过程 - 数据库(内核) - 清泛网 - 专注C/...
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pt-table-checksum校验数据一致性。
从库mysql操作
GRANT SELECT,PROCESS, SUPER, REPLICATION SLAVE ON *.* TO 'checksums'@'192.168.1.100' IDENTIFIED BY 'slavecheck'; flush privileges;
主库mysql操作
GRANT SELECT, PROCESS, SUPER, REPLICATION SLAVE ON *.* TO 'checksums'@'19...
MySQL CONCAT returns NULL if any field contain NULL
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convert the NULL values with empty string by wrapping it in COALESCE
SELECT CONCAT(COALESCE(`affiliate_name`,''),'-',COALESCE(`model`,''),'-',COALESCE(`ip`,''),'-',COALESCE(`os_type`,''),'-',COALESCE(`os_version`,'')) AS device_name
FROM devices
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The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or
...urn the ith sequential element of x.
For lists, one generally uses [[ to select any single element, whereas [ returns a list of the selected elements.
The [[ form allows only a single element to be selected using integer or character indices, whereas [ allows indexing by vectors. Note though tha...
How to get first record in each group using Linq
...roup element by element.F1
into groups
select groups.OrderBy(p => p.F2).First();
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Multiline strings in VB.NET
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I used this variant:
Dim query As String = <![CDATA[
SELECT
a.QuestionID
FROM
CR_Answers a
INNER JOIN
CR_Class c ON c.ClassID = a.ClassID
INNER JOIN
CR_Questions q ON q.QuestionID = a.QuestionID
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'Java' is not recognized as an internal or external command
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For Windows 7:
Right click on My Computer
Select Properties
Select Advanced System Settings
Select Advanced tab
Select Environment Variables
Select Path under System Variables
Click on Edit button
In Variable value editor paste this at the start of the line
C:\Progr...
JavaScript: how to change form action attribute value based on selection?
I'm trying to change the form action based on the selected value from a dropdown menu.
5 Answers
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