The question originates from this article: MySQL answering questions using filesort VS using temporary in the article: mysql> explain select * from t1 force index(id), t2 where t1.id=1 and t1.col1 = t2.col2 order by t2.col1 ; +----+-------------...
< H2 > user table: user field: id,parentid (the ID,0 of the superior is the top level) < H2 > < H2 > Statistical report: report field: time,u_id,pay, description: only one row of data is stored per user per day < H2 > < H2 > user subordinate table: u...
The offer values of 1 and vue are set as follows: offer: { isshow:false, sum_total_price:0, sum_discount:0, sum_price:0, children:[] } The axios submission code under 2 and vue...
there is a table to store temperature information for displaying broken lines on the page. The structure is as follows CREATE TABLE `temp` ( `id` varchar(40) NOT NULL, `duuid` varchar(40) DEFAULT NULL, `temp` int(11) DEFAULT NULL, ...
could not initialize proxy-no Session error occurs when querying data after dubbo+SSH application starts the environmental background of the problems and what methods you have tried tried to add serialization types to the configuration related c...
Why can t you find scoreList in if else ...
found occasional data loss in mysql. This time I lost a record in the order table. I used laravel framework . generate order retention user submit order-> Table 1 generate order-> user payment-> payment callback-> Table 1 status modification, insert...
two hypotheses A $do->query( "INSERT INTO `abc` ( `public_order_id`, `add_time`, `status` ) VALUES ( {$public_order_id} , {$add_time} , ) &...
for a project built with ssm framework and dbcp used to connect to the pool, it is always slow to connect to the database for the first time after starting the project. I found it on the Internet, saying that skip-name-resolve was added to my.cnf and tha...
problem description Chinese cannot be inserted into the Mysql command line under Windows. the environmental background of the problems and what methods you have tried Environment: Win10 Mysql5.5 try: 1. 2.set names utf8 3. utf8 4.CMD chcp 650...
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problem description Design a purchase, sale and inventory system for a medium-sized multi-store seller; in order to improve sales opportunities and reduce the production of expired goods, items will be transferred back and forth among multiple stores...
Mysql: since repeatable RR transaction isolation solves the problem of phantom reading, what are the advantages of serializable isolation over RR isolation? ...
question 1 is the transmission between master and slave databases encrypted? If not, can it be set manually? question 2 can I configure the master-slave database in this way? Master database is placed in the cloud, such as Ali; slave databa...
if it is a single index, it is understandable that the underlying data structure is a B+ tree, but if it is a joint index, it does not feel clearly explained after searching for a long time. saw an article mentioned, but felt that the article was wrong...
problem description I want to query whether a field is null. If it is null, the query result returns flase. If it is not null, the result returns true. What should I do? Because the field value is very long, and you don t need to get the value of the...
at present, the master and slave Synchronize of MYSQL has been done. Now we are considering the issue of log capacity, which has been exploded by binlog. Master-slave mysql-bin and slave relay logs exist. I would like to ask if there is a way to automat...
problem description to implement a multi-field fuzzy query, check the syntax of CONCAT (field 1, field 2, field 3) like in mysql, but sql server does not support this syntax. Ask if there is any way to implement multi-field fuzzy query . the environm...
add the return statement and you will report an error, but if you don t add it, you will ok,. Why? router.post( aaaa , upload.any(), function (req, res, next) { sql.getConnection(function (err, connection) { if (err) throw err; ...
topic description the database has a list of name data as follows * * Biography of Chuqiao Episode 1 Biography of Chuqiao Episode 2 . Biography of Chuqiao Episode 10 * * or Biography of Chuqiao 02 Biography of Chuqiao 02 . Biography of Chuqi...
1 want to use java to develop gui interface, but not in mac system. It is troublesome to say on the Internet? the development tool idea used 2 what is the best way to use java to develop gui interface? ...
I use the plug-in mini-css-extract-plugin to extract less files and css as separate files, which were introduced during development, but after packaging, they will not generate css files, all in accordance with the online configuration, can anyone help ...
how reactnative creates a rendered component how to put a rendered component into a new component there is no related code because I don t know how to write it the specific problem is that he wants to keep a living webview so that he can use it eve...
for example, I just started golang to import a third-party package, and then returned to generate an object. The object println says it is a map, but I can t get out the key, under map, so I want to see what properties and methods are available under th...
my project will use webp image format, because I am a novice, so I can not find on the Internet can directly use the java library to convert picture format bit webp, but google provides a conversion tool that can be run under linux, so I intend to use t...