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MySQL Study Notes _ 7_MySQL common built-in functions and Study Notes _ 7_mysql MySQL common built-in functions Note: 1) it can be used in SELECT/UPDATE/DELETE and where, orderby, and having. 2) use the field name as a parameter in the function. The value of the variable is the value of each row corresponding to the field. 3) In programming languages such as functions provided in C ++, most MySQL function

Python Study Notes (6) and python Study Notes I. Classes and Instances The first object-oriented program: class Student(object): def __init__(self, name, score): self.name = name self.score = score def print_score(self): print '%s: %s' % (self.name, self.score)bart = Student('Bart Simpson', 59)lisa = Student('Lisa Simpson', 87)bart.print_score()lisa.print_score()The class name is

Mysql Study Notes-mysql database installation and mysql Study Notes 1. Run the mysql installation package and select Custom installation (the installation path should not contain Chinese characters; otherwise, an error will occur during installation !) 2. For a mysql instance to be successfully operated, three parts are required: server side, data segment, and data. 3. Server Software Directory: 4

C ++ Study Notes (10): iterator and Study Notes Generator We all know that we can use subscript operations to access string objects and vector objects. There is also a more general method that can be implemented. The name is iterator ). Similar to pointers, The iterator also provides indirect access to objects. As far as the iterator is concerned, its object is a character in the element or string in the co

Python Study Notes (7) and python Study Notes 1. dynamically add attributes and methods to a class: 1. dynamically add attributes and methods to an instance: The method bound to an instance does not work for another instance. Class Student (object): passs = Student () s. name = 'Michael '# dynamically bind an attribute print s to the instance. namedef set_age (self, age): # define a function as the instance

Introduction to HTML Study Notes (1) and introduction to html Study Notes 　　HTML(HyperText Markup LanguageHypertext Markup Language). 'hypertext 'indicates that a page can contain not only text information, but also images, links, and other non-text elements. Html, js, and jq are used togetherWebsite front-end developmentLanguage.XMLStandard, usePairedTags to program and generateDirectly executed by the bro

HTML Study Notes (2) color system and Study Notes System There are three types of Color Representation for html pages:English Representation,Hexadecimal RepresentationAndDecimal. The color passes through the three primary colorsRed, green, and blueThe three types are mixed in proportion. For example, the red decimal format is, 0, and 0. That is, the weights are 0 ~ 255,255 is the maximum, and 0 is the mini

(Linux Study Notes 1: Compressed) [20180209], Study Notes 20180209Study Note 1: compress the file extension by compressing the command at a.m. on April 9, February 5, 2015 *. tar, * .tar.gz ,*. tgz ,*. gz ,*. Z ,*. bz2 common compression commands gzip and bzip2, bzip2 compression ratio gzip is better tar can be used for file packaging, and supports gzip and bzip2 compressed tar-jvc-f filename.tar.bz2/direct

C ++ study notes 5 Containers and Study Notes containers 1. Use assign The assign operation first deletes all elements in the container, and then inserts the new elements specified by its parameters into the container. Like the constructor for copying container elements, if the two containers have the same type, their meta If the element type is the same, you can use the value assignment operator (=) to ass

Mysql Study Notes (log management), mysql Study Notes Logs: mysql logs that record the running status, daily operations, and error information of the database: Binary logs, error logs, and query logs. Binary log: records database operations in binary format, but does not record query statement error logs. This log records mysql server startup, information such as disabling and running errors query logs. Th

Swift 2.0 Study Notes (Day 12) -- talk about several special operators, swift Study Notes For Original Articles, please reprint them. Reprinted Please note: Guan Dongsheng's blog In addition to some common operators, there are also some other: • Reference Number (.): operator such as instance call attributes and methods. • Question mark (?) : Declares the optional type. • Exclamation point (!) :

MySQL self-study (III) and mysql self-study MySQL Data Type MySQL supports multiple data types, including numeric, date, and string.Value Type MySQL mainly provides INTEGER types: TINYINT/SMALLINT/MEDIUMINT/INT (INTEGER)/BIGINT You can add the AUTO_INCREMENT auto-increment constraint to the property field of the integer type. 1. Integer type in MySQL Value range of Integer type 2. floating point type and

Grunt Study Notes (for beginners) and grunt Study Notes 1. Before learning grunt, you must first have a simple understanding of nodejs. The steps for installing nodejs are simple. Install nodejs as prompted on the official website. Http://www.nodejs.org/ 2. Grunt Introduction Grunt is an automated project building tool. if you need to repeatedly execute tasks such as compression, compilation, unit testing

Linux cainiao Study Notes-system partitioning and linux Study Notes Hard Disk Partition knowledge Primary partition: up to four Extended partitions: used to break the limit of up to four primary partitions * Up to one * A maximum of four primary partitions and extended partitions can be created. * Data cannot be written and can only contain logical partitions. Logical Partition Format: write data to the fi

Java Study Notes 27, java Study Notes Vector is the implementation class of the List interface and supports all functions of the List interface. The Vector class is a List class implemented based on arrays and encapsulates a dynamic, The Object [] array that allows redistribution. The Vector is thread-safe and requires no program to ensure the synchronization of the set. Some methods of the Vector class a

[Database Study Notes] (1) JDBC driver category and Study Notes jdbc There are several methods for jdbc to load database drivers: Type 4: Local protocol driver Type 1: jdbc-odbc bridge Jdbc-odbc bridge is provided by sun and is a standard api provided by jdk. this type of driver actually transmits all jdbc calls to odbc, and then odbc calls the local database driver code. (the local database driver

CUBRID Study Notes 27 Data Type 4, cubrid Study Notes Range comparisonComparison between numbers and strings The string is converted to double. SELECT I FROM t WHERE I I ================== 1 2 3 4Comparison of string and date and time Convert string to date or time SELECT s FROM t2; S ====================================== '2014/1/123' '2014/1/123' '2014/1/123' SELECT s FROM t2 WHERE s S =============

HTML study note 2 (Back to Top and back to bottom), study note back to top Back to Top back to bottom Two methods to return to the topI. Use js $ ('Html, body '). animate ({scrollTop: 0}, 'save'); // $ ('html, body') with animation '). scrollTop (0); // No animation $(window).scroll(function () { //You've scrolled this much: $('p').text("You've scrolled " + $(window).scrollTop()

JavaScript advanced programming (Third edition) Study Notes (2), javascript Study NotesChapter 5 Literal representation Var person = {name: "a", age: 10, 5: true // The value property name is automatically converted to a string }; "First name" contains a space, so it cannot be accessed using dot notation, but it can be accessed by person ["first name"] Each item of the array can save any type of data.

C/c ++ Open Course Study Notes-Hacker code analysis and prevention, and wisdom podcast Study Notes Hacker code Analysis and Prevention notes [Course Introduction] C/C ++ language is similar to the underlying computer language except assembly. Currently, mainstream operating systems such as windows, linux, iOS, and Android are all written in C/C ++, therefore, many viruses and Trojans are implemented using