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When to use single quotes, double quotes, and backticks in MySQL
...le and column identifiers, but are only necessary when the identifier is a MySQL reserved keyword, or when the identifier contains whitespace characters or characters beyond a limited set (see below) It is often recommended to avoid using reserved keywords as column or table identifiers when possibl...
Why does “_” (underscore) match “-” (hyphen)?
...cluding zero characters).
(From section 3.3.4.7. Pattern Matching in the MySQL documentation.)
If you want to use the underscore in like as a literal, you have to escape it:
select * from a where name like '%taz\_manual%.pdf%';
...
Why use sprintf function in PHP?
...example, forcing 2dp, 4-digit numbers, etc. It's quite useful for building MySQL query strings.
Another advantage is that it allows you to separate the layout of the string from the data being fed into it, almost like feeding in paramaters. For example, in the case of a MySQL query:
// For securit...
Get record counts for all tables in MySQL database
Is there a way to get the count of rows in all tables in a MySQL database without running a SELECT count() on each table?
...
技术人员如何创业《四》- 打造超强执行力团队 - 资讯 - 清泛网 - 专注C/C++...
技术人员如何创业《四》- 打造超强执行力团队好的团队是创业公司成功的必要因素之一。差劲的团队会导致整个团队没有战斗力，互相算计，只看到自己的利益，永远做不成一个好的产品。优秀 好的团队是创业公司成功的必...
Should Gemfile.lock be included in .gitignore?
...ee CRM.
My preference is postgres, but we want the default database to be mysql2.
In this case, Gemfile.lock still needs be checked in with the default set of gems, but I need to ignore changes that I have made to it on my machine. To accomplish this, I run:
git update-index --assume-unchanged G...
What columns generally make good indexes?
...er to use index */
Since "buyer_id" is referenced in the SELECT portion, MySQL will not use it to limit the chosen rows. Hence, there is no great need to index it. The below is another example little different from the above one:
SELECT
buyers.buyer_id, /* no need to index */
country.name /*...
【动图】AppInventor2如何播放gif动图？如何播放动画？ - App Inventor 2 ...
...会发现图片不会动，只会展示静态图片。那么问题来了，如何展示动图/动画效果呢？
播放动态图，两种思路：
1、使用网络 url 的 gif 图片，设置为 web 浏览器的链接地址，会自动播放网络动图，一直循环播放不能控制停止，...
How to find Unused Amazon EC2 Security groups
... from complete. So I decided to write my own script. I used the AWS CLI, MySQL and some “Bash-foo” to perform the following:
Get a list of all EC2 security groups.
I store the group-id, group-name and description in a tabled called “groups” in a MySQL database called aws_security_groups ...
CMake使用教程 - C/C++ - 清泛网 - 专注C/C++及内核技术
...中找到这个手册对应的代码。
1、Step1。
（如果不知道如何使用cmake，以及如何使用编译产生的Turorial.exe，可先看下前面“CMake使用步骤”的说明，它以Step4为例详细介绍了使用过程，Step1的配置可能不够完全，比如无法运行make...