Tag:Li Si

  • Electronic single interface source code: one access, four links and one access, Baishi, post, Shunfeng, Debang, Jingdong


    The express 100api electronic face-to-face single interface can support 45 + Express Companies (Sitong Yida, Baishi, postal, Shunfeng, Debang, etc.). It can also connect with SF. When connecting with SF, you can choose to use SF’s electronic face list service or express 100api’s electronic face list service. Express 100api provides electronic face list interface for […]

  • SQL addition, deletion, modification and query — 19 database review and preparation


    Zucc   BK armanon   January 5, 2021 1. Select query (1) Basic format SELECT a FROM b WHERE c=d a: It can be * all columns or column names b: Table name queried c: Column name of where clause d: Data for where clause Example: the table name is data name ID sex Zhang […]

  • ES6 grammar learning


    Aside: I haven’t updated it for a long time. I learned some new things when learning react.js these days. Record it.1. Deconstruction assignmentLiterally: assign values one by one according to the structure of the object.(1) . common variables //ES5 let a = 1, b = 2; //(ES6) let [a, b] = [1,2]; If the positions […]

  • Top ten commonly used string functions in MySQL


    Database function is a module with some function, which can receive zero or more input values and return an output value. MySQL provides us with many system functions for processing and analyzing data. This paper introduces 10 common string functions and other related functions. CONCAT() The concat (STR1, STR2,…)) function is used to return the […]

  • How to calculate the median of a set of data in MySQL?


    To get the median of a set of data (for example, the median revenue of a region or a company), we generally divide this task into three sub tasks: Sort the data and give each row of data its ranking in all data; Find the median ranking number; Find out the value corresponding to the […]

  • About converting column values to column names in MySQL


    We sometimes have this need:This presentation related to column values is sometimes very intuitive. I will use a small demo to realize this kind of operation. Table structure create table demo1( Sname varchar (20) not null comment ‘student’, Course varchar (10) not null comment ‘account’, Score float not null comment ‘score’ ) Insert the following […]

  • 41 skills that JS development must know [continuous update]


    preface JS is the core of the front end, but you may not know some skills;This paper combs 41 skills of JS to help you improve your skills in using JS;The article is a little long. You can clone the source code and directly roll up the source code addressPlease stamp all the source code, […]

  • Difference between export and export default


    I believe that many beginners will often see the use of export and export default when learning Vue, but what is the difference between the two? 1. Both export and export default can be used to export constants, functions, files, modules, etc\2. You can import it in other files or modules by means of import […]

  • Topn implemented in PHP code


    Take the first n data in a pile of data according to the score value from large to small, and use the method of small root heap. The specific code is as follows: top_n = $top_n; } /** *Add an element *@ param number $score sort value *@ param mixed $value element */ public function […]

  • MySQL transaction details summary and analysis [update]


    Transaction base route Transaction definition A transaction is a collection of DML statements. Transactions ensure the consistent operation of data in the database. Storage engine In daily development, our common storage engines include InnoDB and MyISAM. However, MyISAM does not support transaction operations. Transaction commit method Sample code CREATE TABLE `user` ( `id` int(10) UNSIGNED […]

  • Several common sorting codes


    catalogue Simple code Use the sort that comes with go Sort [] int type Sort [] float64 type Sort [] string type Custom type sorting Portable usage sort. Slice Portable usage sort.slicestable summary Simple code I found several common sorting codes in my notes, including “bubble sorting, selection sorting, binary sorting and quick sorting”. About […]