how to check the total number of records returned by answering query conditions in query pagination: select top 10 * from (select row_number() over(order by id asc) as rownumber,* from com_system_menu) temp_row where rownumber>((2-1)*10); the nu...
the leased mysql database of Tencent Cloud has more and more data every day, and almost no deletion has been done. Tencent Cloud displays about 1200 gigabytes, but I use the following sql statement to query the size of each table. With the index, it is...
I have been working for a year and a half, and I am also proficient in curd in business. I have also learned high-performance mysql and seen design patterns. I am currently learning the use of redis, but I am confused now. I do not know how to develop in...
problem description run the sql file directly using navicat. Error 1064: [ERR] 1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ; but if you copy the text ...
for example, after the user uploads the profile photo, the image address is stored in the database. Is the address string here similar to WEB-INF image a.jpg? ...
Boss, the following sentence SQL, the execution time has reached 6s, what should I do? in the end, I chose the scheme of "create a separate index " with the least impact. not sure this is the best result! just because of my environment, comprehens...
mysql can different tables FOR UPDATE multiple times in one transaction? ...
I read some articles saying that it is necessary to set a reasonable deadlock timeout for deadlock problems. However, some say that InnoDB will automatically detect transaction deadlocks and roll back immediately with an error. I tried it and found th...
I initialize the mysql database and log in by initializing the password, but I cannot log in after modification. -sharp usr taotie mysql bin mysqld --defaults-file= usr taotie mysql my.cnf --user=taotie-dber --initialize -sharp mysqld_safe --defau...
to ask a question, (MySQL) table A has code_name,code_id,code_field at the end, and table B of another table has many attributes, such as nationality, place of origin, and so on. The nationality subquery method is select code_name form A table where cod...
problem description MySQL 5.7.35 database has a table test, in which there is a field content which is of JSON type and contains data in JSON format the server is Windows Serer 2012 with MySQL Connector ODBC version 5.3 installed query the JSON fiel...
I have table an and table b, and some of the fields in the two tables are the same (if there is a field xmemery yjournal z). I want to assign the value of the same field in table a to b, but I have a table c, which is the information of all users. The on...
there are two existing text tables (some fields are different). If you want to random N pieces of non-duplicated data from these two article tables, how do you write the SQL statement? ...
how can the data shown in the following figure be stored in the mysql database? 45: how do I store the classification and group information of trademarks? And the receptionist can conduct multiple queries (multi-conditional search)? what I ve come...
A table field has 3 records returned by separate query B table field alone query has 8 records returned currently these two tables have no primary key and foreign key if you want to combine, how should the structure of the table be designed an...
how is Zhihu s database designed? what I don t understand is how Zhihu s questions and concerns are designed? agree with the answer, focus on the question, and how is it stored? ...
how to modify the record and return the record content and query the record at the same time, these are actually two aspects of the same problem, but can not be regarded as one problem; after modifying a record, how do I get the value of the modified...
the problem I face now is I have a datasheet that is almost 1 million. it s not a way to go on like this. how can I separate it out, but I can still use the data from the datasheet? because suppose I export it to the drop table I can t use it ...
upload and display items of pictures album table album (field: album_id userid title...) picture table photo (field: photo_id albumid path...) A photo album contains multiple pictures more pictures are uploaded in one day. Consider horizontal sub...
problem description Why the ID (student_id) of students who fail in my score table (num < 60) cannot use having select student_id from score having num < 60; can only use select student_id from score where num < 60 ; the environmental background ...
see a saying on the Internet < hr > Sequential IO mode (Queue Mode) concurrent IO mode (Burst Mode): disk controller may issue a series of IO commands to the disk group at a time, which is called sequential IO; if the disk group can only execute one...
problem description in the code currently written, in common.js. Already. Then () once. Why in the vue component. We need to do it again. Then (). Is there any way to get the desired res data directly using this.common.Login ()? related codes comm...
when does Wechat s enterprise pay for the change and need to get the user openid, this openid? our requirement is for users to initiate a withdrawal application in APP, submit Wechat s account number and name, then save the withdrawal application re...
first introduce the situation: 1. Python is decompressed with zip and configured with environment variables. Python can be run under cmd. 2, https: bootstrap.pypa.io get. downloaded the script and ran python get-pip.py to complete the download. 3...
there is currently only one field in the form form. Name, now needs to add a few values to the form data() { return { form form: { name: "" } } }, methods: { getCheckedNodes() { ...