Mysql creating table issue - mysql

I started learning SQL but just in my first query, failed, i was doing exactly the same as the mentor explaining in the course but somehow his code worked mine not.
I also tried this query on PopSql it also did not work.
What is wrong here?


You need to select the database you are running this query on.
To do this via MySQL Workbench:
Click on the 'Schemas' tab highlighted below:
Then double click on the name of the database you are trying to run the query on, the database name will be bolded once selected.


You need to tell MySQL which database to use:
USE database_name;
before you create a table.
In case the database does not exist, you need to create it as:
CREATE DATABASE database_name;
followed by:
USE database_name;

Related

MySQL can't show table after altering auto_increment

I created two tables like this
and I want to change the added data's id so I use
alter table member auto_increment=5;
after this, it couldn't show my member table. It shows
error 2013: lost connection to MySQL server during query.
I thought my table is too big to run, so I changed the limit and the DBMS time out, but it didn't work either. Can someone tell me what's the problem now?

I found the problem. Don't edit your MySQL database when you're connecting it with your Python Flask program. Edit means any CRUD actions.

Easy edit and delete row from mysql

I'm not that good at mysql but some of my tables has this line where I can edit and delete the row easy without writing any SQL? How can I make that row inside another table?

You can use any GUI editor like phpmyadmin or the tools which P.Salmon mentioned.
Using GUI editor, you can connect to the database using connection string and you can view tables and see the result which can edited and deleted.

How do I change the database name using MySQL? [duplicate]

This question already has answers here:
How do I rename a MySQL database (change schema name)?
(46 answers)
Closed 9 days ago.
How can I change the database name of my database?
I tried to use the rename database command, but on the documents about it it is said that it is dangerous to use. Then what should I need to do to rename my database name?
For example, if I want to rename my database to this.
database1 -> database2?

Follow bellow steps:
shell> mysqldump -hlocalhost -uroot -p database1 > dump.sql
mysql> CREATE DATABASE database2;
shell> mysql -hlocalhost -uroot -p database2 < dump.sql
If you want to drop database1 otherwise leave it.
mysql> DROP DATABASE database1;
Note : shell> denote command prompt and mysql> denote mysql prompt.

I don't think it's possible.
You can use mysqldump to dump the data and then create a schema with your new name and then dump the data into that new database.

Unfortunately, MySQL does not explicitly support that (except for dumping and reloading database again).
From http://dev.mysql.com/doc/refman/5.1/en/rename-database.html:
13.1.32. RENAME DATABASE Syntax
RENAME {DATABASE | SCHEMA} db_name TO new_db_name;
This statement was added in MySQL 5.1.7 but was found to be dangerous and was removed in MySQL 5.1.23. ... Use of this statement could result in loss of database contents, which is why it was removed. Do not use RENAME DATABASE in earlier versions in which it is present.

"As long as two databases are on the same file system, you can use RENAME TABLE to move a table from one database to another"
-- ensure the char set and collate match the existing database.
SHOW VARIABLES LIKE 'character_set_database';
SHOW VARIABLES LIKE 'collation_database';
CREATE DATABASE `database2` DEFAULT CHARACTER SET = `utf8` DEFAULT COLLATE = `utf8_general_ci`;
RENAME TABLE `database1`.`table1` TO `database2`.`table1`;
RENAME TABLE `database1`.`table2` TO `database2`.`table2`;
RENAME TABLE `database1`.`table3` TO `database2`.`table3`;
http://dev.mysql.com/doc/refman/5.7/en/rename-table.html

You can change the database name using MySQL interface.
Go to http://www.hostname.com/phpmyadmin
Go to database which you want to rename. Next, go to the operation tab. There you will find the input field to rename the database.

InnoDB supports RENAME TABLE statement to move table from one database to another. To use it programmatically and rename database with large number of tables, I wrote a couple of procedures to get the job done.
You can check it out here - SQL script #Gist
To use it simply call the renameDatabase procedure.
CALL renameDatabase('old_name', 'new_name');
Tested on MariaDB and should work ideally on all RDBMS using InnoDB transactional engine.

I agree with above answers and tips but there is a way to change database name with phpmyadmin
Renaming the Database
From cPanel, click on phpMyAdmin. (It should open in a new tab.)
Click on the database you wish to rename in the left hand column.
Click on the Operations tab.
Where it says "Rename database to:" enter the new database name.
Click the Go button.
When it asks you to want to create the new database and drop the old database, click OK to proceed. (This is a good time to make sure you spelled the new name correctly.)
Once the operation is complete, click OK when asked if you want to reload the database.
here's the video tutorial:
http://support.hostgator.com/articles/specialized-help/technical/phpmyadmin/how-to-rename-a-database-in-phpmyadmin

Another way to rename the database or taking an image of the database is by using the reverse engineering option in the database tab. It will create an ER diagram for the database. Rename the schema there.
After that, go to the File menu and go to export and forward engineer the database.
Then you can import the database.

Sequel Ace database client have a rename database functionality. Select the database you would like to edit and click Database in the menu and then click Rename Database from the dropdown. Rename the database and ckick rename. Done!

After much aggravation this is what I have found to work"simply".
First thing, I am using MYSQL Workbench and the import would not work as it should, as the import dump file would always revert to the original schema name.
I spent several hours trying every thing to no avail,all for a spelling error.
I solved the issue by opening one of the .sql dump files in notebook and hand editing the typo's of the schema name, take care to rename all instances schema name has three in the beginning, save the file and then import. this worked perfectly for me and hope that it will help others looking for the simple answer to changing database names/schema names.
One more tip that I have found true, when programs do not do as they should go to the "source" literally find the source code.
Hope this helps someone
Low rep so they wont let me comment on the prior/post answer(it keeps changing rank or position), so I added it here. reverse engineering will work fine as long as there is no data in the sever table. if data exists and you try to update the server after the name change it will either pull an error or just create a new database/schema with no data, I know I tried ten times to no avail.
The above works simply and avoids headaches, as one can review the SQL code for other errors if any or change table names or creation data.
the .sql file is just a compiled SQL code so in theory one could copy and add it through PHP or the script console of the database management tool.

You can use below command
alter database Testing modify name=LearningSQL;
Old Database Name = Testing,
New Database Name = LearningSQL

Go to data directory and try this:
mv database1 database2
It works for me on a 900 MB database size.

Try:
RENAME database1 TO database2;

Selecting a Database

I am using PHPMyAdmin that is a part of cPanel for a website of mine. My question is this: How can I specify a database such that I can create tables etc for the specified database.
My database name is canningi_db_person_cdtest
Currently, I am using the following statement in the Query textbox:
use canningi_db_person_cdtest
I get the following information:
Your SQL Query has been executed successfully
The webpage then refreshes, and if I try and create a table, I am getting the following error:
No database selected
What should I do?

You need a semicolon at the end of the database name. For example:
USE database;
SELECT * FROM table
https://dev.mysql.com/doc/refman/5.0/en/use.html

Trying to open this URL in your Web Browser :
http://localhost/phpmyadmin/
and then you can see all of database lists.
or if you using SQL command, try this :
use YOURDATABASENAME;

Any way to view ALTER TABLE after its been executed? -MySQL

In the same way SHOW CREATE TABLE tblname; brings back what was previously executed, is there anyway to view the SQL of an ALTER TABLE query?
Please help?

One small clarification: show create table does not actually "bring back what was previously executed". It just shows you the DDL that would create the table from scratch. The table may have been created and then altered many times, but show create table reflects the current state of the table.
As for finding any alter table statements that ran on the table recently, the best bet is the binary log.
First check to see if binary logging is enabled:
show variable like 'log_bin';
If it is, find the binary log for the relevant time period, use mysqlbinlog to convert it to SQL, then grep for the relevant table name to find the alter table statement you are looking for.

Tools:
Maatkit.
Red-Gate's MySQL Schema & Data Compare
Toad
SQLYog
MySQL Diff
Manual:
First check to see if binary logging is enabled:
show variable like 'log_bin';
Then,
mysqlbinlog /var/log/mysql/mysql-bin.000001 | grep 'alter table *tablename*' > test.file
Go to test.file to see the alter statements.

If your MySQL instance has logging turned on, you can view the logs. This would be the best option.
If your system has history turned on, you can start a client back up from the same system and try the up arrow. You might be able to see the command there.
If you know the user that ran the command and they happened to run it directly from a command line, the same history trick might work.