How to run multiple instances of MySQL Server on one server is in the MySQL manual: https://dev.mysql.com/doc/refman/8.0/en/multiple-servers.html

UPDATE Employee SET SupervisorID = ( SELECT ID FROM Employee WHERE EmployeeSRN = ? ) WHERE EmployeeSRN = ? ; (Someone else can advise on how to substitute values into the query for C# without risking sql-injection.)

max_connections limits the number of simultaneous connections. max_user_connections limits the number of simultaneous connections from any one user. A single program, including a single instance of Workbench, should (normally) make only one connection. Some novice programmers make a connection inside a subroutine and fail to disconnect. What they should do is have a single connection for all database activity in the program. "Reserving 1 for MWB" -- Let me ramble on for a moment before addressing this. "Applications" and "users" should each have their own login. 30 users should be using more than a single login. Otherwise, there is no hope of tracking them. No "user" and no "application" should connect as the SUPER user (typically called 'root' or 'admin') except when doing admin stuff. Your use of Workbench may qualify for "admin stuff", so you could be justified in connecting as 'root'. MySQL reserves 1 connection (of the max_connections) for 'root'. Actually, if max_connections is 100, and you connect as root, then you can see 101 connections in the extreme case. There is only 1 'free pass', so don't load up MWB twice if all the 'users' are 'root', too. Summary Configure Workbench to log in as user 'root; give everyone else a non-super login.

You can qualify your tables/columns in your query to separate. It's difficult to imagine what you are trying to do without seeing a sample of the data. You could also prefix/pipe in descriptive text in your id columns to help separate the ids. `Select 'supplier1-' || id, 'supplier2-' || id2 From Table;

Not SET new.vaccination_Status, SET patient.vaccination_Status I would prefer to create a Stored Procedure that does whatever is needed to both tables, and maybe other tables.

Seems to me like the PREREQUISITES table materializes the N-M relationship between courses. I have no idea how MySQL Workbench works (or even what it is), but in plain SQL, it would be something like this ... Assuming a COURSES table like this: create table courses ( course_id int primary key, course_name char(50) ); The PREREQUISITES table would look like this: create table prerequisites ( course_id int references courses, prereq_course_id int references courses, primary key (course_id, prereq_course_id) );

Try with an updated version of MySQL Workbench, the latest version currently is 8.0.26 If it doesn't work, they will probably have to use a more "basic" tool like a shell "mysql". https://dev.mysql.com/doc/refman/8.0/en/expired-password-handling.html You may also have to check what the disconnect-on-expired-password parameter is at : https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_disconnect_on_expired_password

-- Получаем суммы по дням: select paydate ,sum(money) from expenses group by paydate -- Далее из этого самый простой вариант: select max(money) from expenses where paydate = ( select paydate from expenses group by paydate order by sum(money) desc limit 0, 1 )

With correct access rights to the database database Both requests are correctly performed in a console client and in MySQL Workbench. The fact is, in the last editor, we need to closely monitor the installation from the new user. If you do not provide a default database in the field when the compound is formed Default Schemathe situation you have described is that the request is not being implemented without a clear detail of the database name.In a consulated client, you will not be able to execute the request without detailing the database name. databaseif the database was clearly not selected at the time of installation of the compound or by team USE♪

It would be better to think about normalization, because CSV is a very bad way to store. At the same time, this will allow for a rotating field of order (absolute or bundle).In the present form of presentation, I would suggest that this CSV be converted into JSON-Massiv. Either change the storage structure or do it directly in the request (usual CONCAT is sufficient).Next thing you know, passwords and precincts are fine. Either by taking steps at the external office, simply removing, replacing or reapplying (replacement of two elements) by regular JSON-function.

Try this:CREATE DEFINER=`root`@`localhost` PROCEDURE `add_new_teacher_with_check`(id int, f_n varchar(45),s_n varchar(45), sur varchar (45), em varchar(45) ,post varchar(45)) BEGIN IF (select em regexp '.ru$')and (select em regexp '@')and (select f_n regexp '[а-яА-Я]')and (select s_n regexp '[а-яА-Я]')and (select sur regexp '[а-яА-Я]')then insert into teacher(idteacher, first_name, second_name, surname,e_mail,work_place)values(id,f_n,s_n,sur,em,post); END IF; END

Means there is no table test_2.test_2♪ The table may have been deleted or not established.

Use the requestSELECT manufacturer, COUNT(*) AS cnt FROM 'table_name' GROUP BY manufacturer HAVING cnt > 1 https://metanit.com/sql/mysql/4.6.php [1]

CREATE TRIGGER `update_full_price_after_insert` BEFORE INSERT ON sale FOR EACH ROW BEGIN DECLARE price INT; SET @price = (SELECT full_price FROM car_in_stock WHERE car_in_stock.id_car = NEW.car_in_stock_id_car ); SET NEW.full_price_with_discount = @price; END

Got a version of 8.0.21 and it all worked.

It looks normal, all the connections between the tables are perfectly logical, and I don't understand why the posts have field. keywords Not normalized (not included in the handbook), as this has been done categoriesor is that not what I think? I still don't know what's in there. descriptionIf it's the usual text field, there's no question. Ooh. users References name and surname In order to save space, it is possible not to do so unless users are millions, savings will not be very large, and the editing of these fields will be more cumbersome if the handbooks are available.

Db view exists as alias(synonym) for a sample request. Since several tables may be used in the request, the developers have excluded the possibility of directly modifying the data, which is not ambiguously referred to as the view.

I've managed to solve this problem and solve it as usual on the surface. As much as I've changed XAMPP, the base was still 3306, which was "launched" in mysql workbench, which was the MySQL 8.0 version in XAMPP MYSQL 5.7 (both below). Addressing the problem is a launch with a port of 3307:mysql.exe -u root -P 3307After that, the authentication plates stopped confiscating.My assumptions were that there was a line in the properties.ini. mysql_arguments = -u root -P 3306♪ I changed her to ♪ mysql_arguments = -u root -P 3307♪ After some time in the console when you call the team. mysql.exe -u root -P Mysql was connected to port 3306, and the port was in turn occupied by MySQL WorkBench, so he referred to a catalogue I didn't understand, and said that because XAMPP had a MySQL 5.7 version, and that version used an old-fashioned authentication plate. Despite the fact that the change in the properties file.ini did not produce any results in mysql.exe launch, but suggested that ports could be transferred as a parameter. Accordingly, I commanded mysql.exe -u root -P 3307 And he joined the port that I used to build in the XAMPP itself by changing mySQL configuration files.

SELECT e1.name AS employee_name, e2.name AS chief_name, department.name AS department_name FROM employee AS e1 JOIN employee AS e2 ON e1.chief_id = e2.id JOIN department ON e1.department_id = department.id

java.sql. SQLSyntaxErrorExceptionYou have a syntax error in your sql request.String sql = "SELECT id, first, last, age FROM new_table";