I am facing a problem in searching a particular table_name.
I have around 50 databases on the server and i wish to search a table_name say X is created in which all databases.
Is there any straight-forward to find the exact databases in which X table is found in MYSQL through phpMyAdmin.
Any help will be appreciated.
Thanks
You can query the information_schema database for this. The below query will return the names of all the databases, which contains the table your_table_name.
SELECT `TABLE_SCHEMA`
FROM `information_schema`.`TABLES`
WHERE `TABLE_NAME` = 'your_table_name'
I hope this is what you are looking for.
According to the MySQL documentation about information_schema database,
INFORMATION_SCHEMA provides access to database metadata.
Metadata is data about the data, such as the name of a database or
table, the data type of a column, or access privileges. Other terms
that sometimes are used for this information are data dictionary and
system catalog.
Please query the information_schema.TABLES with table_type='BASE TABLE' and providing the name of the table(table_name).
This query will give us all the tables with '<your_table_name>' in all the databases that are currently in our server.
Please change '<your_table_name>' as per your requirement.
SELECT TABLE_SCHEMA, TABLE_NAME
FROM `information_schema`.`TABLES`
where table_type='BASE TABLE'
and table_name = '<your_table_name>'
limit 100;
Related
I have an issue with InnoDB tables. all table status are showing in use.
I am trying to open table but it is giving error "Table 'mysqlbackup.aadhars' doesn't exist in engine"
please help me
Maybe the table belongs to different schema (and not mysqlbackup) I would recommend checking all the table names (along with schemas) and see which schema aadhars table belongs to, e.g.:
SELECT *
FROM information_schema.tables
WHERE table_schema = 'mysqlbackup';
The above query will return the names of all the tables present in mysqlbackup schema. If you want to see which schema aadhars belongs to, try the following query:
SELECT *
FROM information_schema.tables
WHERE table_name = 'aadhars';
I am trying to find the list of MySQL's system tables (or internal tables).
The database "mysql" contains both its system tables (internal or proprietary to MySQL database) and user created tables.
For example, by executing the below query
SELECT table_name, table_type, engine, TABLE_COMMENT
FROM information_schema.tables
Where TABLE_SCHEMA = 'mysql'
order by engine desc;
we get all tables' type as BASE TABLE only. These entries include my user table also (for example, CREATE TABLE mysql.tst1 (i INT) ENGINE = MYISAM;)
Could you please let me know how can we differentiate between internal(or system) tables AND user created tables? Do we have any query or system objects like stored procedure ....etc ...?
how about the below query i guess you missed out the information_schemaand performance_schema
so check out the below query
SELECT table_name, table_type, engine, TABLE_COMMENT
FROM information_schema.tables
Where
TABLE_SCHEMA IN ('mysql','information_schema','performance_schema')
ORDER BY engine DESC
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'
)
Is there any way to know the time when last select statement has been performed on a table? I am using the InnoDB storage engine.
I have tried with the following query:
select update_time,table_name from information_schema.tables where table_schema='databasename';
..but I'm receiving NULL in the update_time column.
Unless you manually update a last_accessed-field on the table, my best bet would be to add query logging and parse the log-files.
I googled and found these relates questions:
When was the last time a mysql table was accessed?
How do you get the last access (and/or write) time of a MySQL database?
SELECT UPDATE_TIME
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'dbname'
AND TABLE_NAME = 'tabname'`
I would like to know how many rows are in each table in my database. I've come so far as to having
select count(*) _tablename_;
However i would need to do that on each and every table - and there are a lot. What would me the best way to get a print-out with the table name and it's row count?
SELECT table_name, table_rows
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = '<your db>';
I also hope you realise there's an error in your query: it's missing a FROM.
This following query will return number of rows in each table but it doesn't seem to return exact value all the time
SELECT table_name, table_rows
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = '<your db>';
TABLE_ROWS: The number of table rows in the partition. For partitioned InnoDB tables, the row count given in the TABLE_ROWS column is only an estimated value used in SQL optimization, and may not always be exact...
for more https://dev.mysql.com/doc/mysql-infoschema-excerpt/5.5/en/partitions-table.html
In addition to SQL queries by others, one can also use Workbench GUI to get the row-counts of each table. To do this, Launch Workbench -> Connect to Db -> right click Db and select "Schema Inspector" (as in Screenshot below - I have highlighted the "Rows" column):
HTH.