I have multiple databases all having the same table structure on one server.
I need to change three tables in all databases which name is
xx_databasename
where xx is an isoAlpha2Code of the country the database os connected to.
So how can I perform a query like
DROP TABLE IF EXISTS tablename;
CREATE TABLE tablename (....);
on each database with just one mySQL command?
Related
I have a number of federated tables on my MySQL 5.7.23 and MariaDB 10.1 servers (I was using CREATE SERVER syntax if this matter).
I can easily get a list of these tables using query:
SELECT * FROM `information_schema`.`TABLES` WHERE `ENGINE` = 'Federated';
However, I need to get connection information for all these tables:
CREATE TABLE `table` (
-- table definition here
)
ENGINE=FEDERATED
CONNECTION='server/table' -- <= I would like to get this info
;
Not the servers I created that are in mysql.servers.
I could not find it in information_schema and mysql databases.
I can only get it from table.frm files or using SHOW CREATE TABLE table; query that is for one table only.
Is it possible to get what I want at all?
Thanks.
I have a MySQL database table which has been listed twice with case sensitive name.
Both table names are pointing to same table, for example Admin and admin
When I checked information_schema it is listed as below:
mysql> SELECT TABLE_CATALOG, TABLE_NAME , TABLE_TYPE, ENGINE, CREATE_TIME
FROM information_schema.tables
where table_schema='school';
How do I clean up this mess?
Usually MySQL does not allow you to create the table with case-sensitive. It will show the error as :
ERROR 1050 (42S01): Table 'admin' already exists
But MySQL allows you to create a temp table with a existing name because they don't have the same "scope". A temporary table is visible in the session only, and it is dropped at session ending. If you have the same name, MySQL "hide" the original table until you drop your temp table.
I would suggest you to take a backup of the existing data and update the MySql version to 5.7 .
I have databases db1 and db2 and I want to copy all tables from db1 to db2. I have tried many times. For one table:
create table backup.(table_name) select from db1.(table_name);
create table backup.* select from db1.*;
You can try:
select * from db1.database into db2.backup
I am having two mysql databases. One is NEW and other one is OLD.
I require the list of different tables between two databases. That is my old database is having the list of 155 tables and my new database is having the list of 165 tables.
How can I get the name of the TEN differnt tables ?
Is there any tool to do that or we can able to do via query ?
Any help will be thankful...
Thanks in advance..
Have you tried:
SHOW TABLES IN database;
or using information schema:
select table_schema,
table_name from information_schema.tables
where table_name = ???;
EDIT AS PER OP'S COMMENT:
The INFORMATION_SCHEMA database is made up of temporary tables using the MEMORY storage engine.. All tables in the INFORMATION_SCHEMA database are stored directly in memory as MEMORY storage engine tables. They are totally internal to MySQL, so the .frm mechanisms are handled in mysqld. In my answer, I first showed the table layout of INFORMATION_SCHEMA.TABLES. It is a temporary table in memory. It is manipulated using storage engine protocols. Thus, when mysqld is shutdown, all information_schema tables are dropped. When mysqld is started, all information_schema tables are created as TEMPORARY tables and repopulated with metadata for every table in the mysql instance.
For e.g. If your run following two commands you will see all the databases in your mysql metadata.
show databases;
use information_schema; show tables;
Here you are specifying a table_schema to get the table names.
SELECT table_name from
information_schema.tables WHERE table_schema = 'mydb';
With a join: assuming one database name is db1, other db2
SELECT table_name from
db1.tables x
inner join
db2.tables
on x.table_name = y.table_name
;
I think you should query on database information_schema. It's a table which contains all meta data of all database.
Query something like:
SELECT * FROM `TABLES` T1
LEFT JOIN `TABLES` T2
ON T1.`TABLE_NAME` = T2.`TABLE_NAME`
WHERE T1.`TABLE_SCHEMA`='xxx'
AND T2.`TABLE_SCHEMA`='yyy'
AND T1.TABLE_CATALOG IS NULL
You can do this by querying the INFORMATION_SCHEMA (a database which contains information of other databases in the server like table names, column names, primary key columns, primary key names, indexes, etc.) like this:
-- this gives the table names that are in the new table but not in the old table
select newTable.TABLE_NAME
from TABLES newTable
where newTable.TABLE_SCHEMA='NEW' and newTable.TABLE_NAME not in
(
select oldTable.TABLE_NAME
from TABLES oldTable
where oldTable.TABLE_SCHEMA='OLD'
)
I have a database db1 which contains tables tbl1, tbl2, and tbl3.
I also have an empty database db2.
Can I create a MERGE table mrg1 which merges the contents of tbl1, tbl2, and tbl3 from database db1, but is stored in database db2?
Yes, if your database is set up to allow you to run queries against multiple databases at once. I think it would look something like this,
INSERT INTO db2.mrg1 (colA,colB,ColC)
(
SELECT colA,colB,ColC
FROM db1.tbl1,db1.tbl2,db1.tbl3
WHERE [whatever joins your tables together]
)