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How do I update if exists, insert if not (AKA “upsert” or “merge”) in MySQL?
...
Note this is not standard SQL. An example from the manual:
CREATE TABLE test (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
data VARCHAR(64) DEFAULT NULL,
ts TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (id)
);
mysql> REPLACE INTO test VALUES (1, '...
c# datatable to csv
...rray();
sb.AppendLine(string.Join(",", fields));
}
File.WriteAllText("test.csv", sb.ToString());
.net >= 4.0
And as Tim pointed out, if you are on .net>=4, you can make it even shorter:
StringBuilder sb = new StringBuilder();
IEnumerable<string> columnNames = dt.Columns.Cast&l...
Is there a difference between YES/NO,TRUE/FALSE and true/false in objective-c?
...hich is why you can evaluate any primitive type or expression as a boolean test (including, e.g. pointers). Note that you should do the former, not the latter.
Note that there is a difference if you assign obtuse values to a so-called BOOL variable and test for specific values, so always use them a...
How can I concatenate regex literals in JavaScript?
... (r1.multiline ? 'm' : ''));
console.log(r3);
var m = 'test that abcdef and abcdef has a match?'.match(r3);
console.log(m);
// m should contain 2 matches
This will also give you the ability to retain the regular expression flags from a previous RegExp using the standard ...
How to record webcam and audio using webRTC and a server-based Peer connection
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@Redtopia In some recent load tests we were able to get 150 one2one connections of webrtc on an i5/16GB RAM. You can expect that these numbers will be better in the future, but don't expect miracles: there is a lot of encryption going on for SRTP, and tha...
JavaScript OR (||) variable assignment explanation
... cannot later do if( true == f ). If an integer was stored in f, then this test will always return false.
– user1115652
Aug 1 '13 at 2:11
9
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How do you get the current project directory from C# code when creating a custom MSBuild task?
...
Both solutions will not work as expected when using Test Explorer.
– Gucu112
Sep 19 '18 at 8:51
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搭建高可用mongodb集群（一）——配置mongodb - 大数据 & AI - 清泛网 - 专...
...ongodb测试文件夹
#存放整个mongodb文件
mkdir -p /data/mongodbtest/single
#存放mongodb数据文件
mkdir -p /data/mongodbtest/single/data
#进入mongodb文件夹
cd /data/mongodbtest/single
2、下载mongodb的安装程序包
wget http://fastdl.mongodb.org/linux/mongodb-...
Get a list of URLs from a site [closed]
...es (some may also support other formats).
Please Note: Google has not tested or verified the features or
security of the third party software listed on this site. Please
direct any questions regarding the software to the software's author.
We hope you enjoy these tools!
Server-side P...
How do I perform an IF…THEN in an SQL SELECT?
...lumnname>
FROM <table>
The extended case:
SELECT CASE WHEN <test> THEN <returnvalue>
WHEN <othertest> THEN <returnthis>
ELSE <returndefaultcase>
END AS <newcolumnname>
FROM <table>
You can ev...