We have 100+ databases with identical schemas on the same server. I need to run the identical select statement on all databases and return the results. I have looked thru several posts about altering many dbs and have tried this:
SELECT CONCAT
('SELECT * FROM ', a.table_schema, '.tableIwant
GROUP BY CONCAT(emp_id, "-", other_id)
HAVING count(CONCAT(emp_id, "-", other_id)) >1')
FROM information_schema.tables a
WHERE a.table_schema LIKE 'table_prefix_%'
GROUP BY a.table_schema;
But all this returns is a list of queries.
I know that I could do this using PHP - build an list of all the dbs with one query, then a WHILE loop over the result set, etc. But I want to do this from MySQL, is there a way?
UPDATE:
Thanks to #KayakJim I have tried to create a Stored Procedure to solve this:
DELIMITER //
CREATE PROCEDURE checkDuplicates()
BEGIN
DECLARE bDone INT;
DECLARE dbname VARCHAR(20);
DECLARE count1, count2 INT;
DECLARE curs CURSOR FOR SELECT table_schema FROM INFORMATION_SCHEMA.TABLES WHERE table_schema like 'table_%' GROUP BY table_schema;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;
CREATE TEMPORARY TABLE IF NOT EXISTS db1.tblResults (
name VARCHAR(20),
countDupes INT,
countDupesAll INT
) ENGINE = MEMORY
;
OPEN curs;
SET bDone = 0;
REPEAT
FETCH curs INTO dbname;
SELECT SQL_CALC_FOUND_ROWS * FROM dbname.table
GROUP BY CONCAT(emp_id, "-", other_id)
HAVING count(CONCAT(emp_id, "-", other_id)) >1;
SET count1 = FOUND_ROWS();
SELECT SQL_CALC_FOUND_ROWS * FROM dbname.table
GROUP BY CONCAT(emp_id, "-", other_id, "-", param)
HAVING count(CONCAT(emp_id, "-", other_id, "-", param)) >1;
SET count2 = FOUND_ROWS();
UNTIL bDone END REPEAT;
CLOSE curs;
SELECT * FROM db1.tblResults;
END;
//
CALL checkDuplicates();
The problem now is that when I execute, it returns an error 1049: Unknown database 'information_schema'. When I take that query and run it alone I get no errors, and it returns a list of databases that match the WHERE clause.
The solution you posted using PHP could be done inside a Stored Procedure, which would keep the logic inside MySQL as you are desiring.
Related
I'm trying to update a column (in this case, a date) that is present on most of the tables on my database. Sadly, my database has more than 100 tables already created and full of information. Is there any way to loop through them and just use:
UPDATE SET date = '2016-04-20' WHERE name = 'Example'
on the loop?
One painless option would be to create a query which generates the UPDATE statements you want to run on all the tables:
SELECT CONCAT('UPDATE ', a.table_name, ' SET date = "2016-04-20" WHERE name = "Example";')
FROM information_schema.tables a
WHERE a.table_schema = 'YourDBNameHere'
You can copy the output from this query, paste it in the query editor, and run it.
Update:
As #PaulSpiegel pointed out, the above solution might be inconvenient if one be using an editor such as HeidiSQL, because it would require manually copying each record in the result set. Employing a trick using GROUP_CONCAT() would give a single string containing every desired UPDATE query in it:
SELECT GROUP_CONCAT(t.query SEPARATOR '; ')
FROM
(
SELECT CONCAT('UPDATE ', a.table_name,
' SET date = "2016-04-20" WHERE name = "Example";') AS query,
'1' AS id
FROM information_schema.tables a
WHERE a.table_schema = 'YourDBNameHere'
) t
GROUP BY t.id
You can use SHOW TABLES command to list all tables in database. Next you can check if column presented in table with SHOW COLUMNS command. It can be used this way:
SHOW COLUMNS FROM `table_name` LIKE `column_name`
If this query returns result, then column exists and you can perform UPDATE query on it.
Update
You can check this procedure on sqlfiddle.
CREATE PROCEDURE UpdateTables (IN WhereColumn VARCHAR(10),
IN WhereValue VARCHAR(10),
IN UpdateColumn VARCHAR(10),
IN UpdateValue VARCHAR(10))
BEGIN
DECLARE Finished BOOL DEFAULT FALSE;
DECLARE TableName VARCHAR(10);
DECLARE TablesCursor CURSOR FOR
SELECT c1.TABLE_NAME
FROM INFORMATION_SCHEMA.COLUMNS c1
JOIN INFORMATION_SCHEMA.COLUMNS c2 ON (c1.TABLE_SCHEMA = c2.TABLE_SCHEMA AND c1.TABLE_NAME = c2.TABLE_NAME)
WHERE c1.TABLE_SCHEMA = DATABASE()
AND c1.COLUMN_NAME = WhereColumn
AND c2.COLUMN_NAME = UpdateColumn;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET Finished = TRUE;
OPEN TablesCursor;
MainLoop: LOOP
FETCH TablesCursor INTO TableName;
IF Finished THEN
LEAVE MainLoop;
END IF;
SET #queryText = CONCAT('UPDATE ', TableName, ' SET ', UpdateColumn, '=', QUOTE(UpdateValue), ' WHERE ', WhereColumn, '=', QUOTE(WhereValue));
PREPARE updateQuery FROM #queryText;
EXECUTE updateQuery;
DEALLOCATE PREPARE updateQuery;
END LOOP;
CLOSE TablesCursor;
END
This is just an example how to iterate through all tables in database and perform some action with them. Procedure can be changed according to your needs.
Assuming you are using MySQL, You can use Stored Procedure.
This post is a very helpful.
Mysql-loop-through-tables
Stored Proc Definition:
DECLARE dbName varchar(255);
DECLARE tableName varchar(255);
DECLARE fullPath varchar(255);
DECLARE conditions varchar(255);
SET dbName = idbname;
SET tableName = itablename;
SET fullPath = CONCAT("'",dbName,"'",'.',"'",tableName,"'");
SET checkExists = 0;
I am creating a stored proc where the dbname and tablename are dynamic, however I am stuck on the select aspect of this query.
I am trying to repalce the _test.user with values passed into the stored proc.
SELECT count(*) INTO checkExists FROM `_test`.`user` WHERE id = 1;
However this line throws an error
SELECT count(*) INTO checkExists FROM fullPath WHERE id = 1;
Error:
Procedure execution failed
1146 - Table 'dbname.fullpath' doesn't exist
I have also tried CONCAT() like this
set conditions = CONCAT('SELECT count(*) INTO ',checkExists, ' FROM ', fullPath, ' WHERE id=', 1);
However I can't figure out even how to use this in a select? Help is appreciated.
I like to do these modifications using replace(). Something like this:
replace(replace('SELECT count(*) INTO checkExists FROM `<dbname>`.`<tname>` WHERE id = 1',
'<tname>', v_tablename
), '<dbname>', v_databasename
)
You may also want to use v_fullpath somewhere. I'm not really sure what query you actually want to create.
I'm not sure why you have a variable called checkExists, when it seems to be the destination file. However, I would suggest that you prepend all your local variables with something to distinguish them from column names.
I have databases named company_abc, company_xyz, etc. Those company_* databases have all the same structure and they contain users table.
What I need to do is to aggregate all users data from just company_* databases and replicate this view to another server. The view would just be something like
COMPANY NAME | USERNAME
abc | user#email.com
abc | user1#email.com
xyz | user2#email.com
company3 | user3#email.com
Is something like that possible in MySQL?
The databases are created dynamically, as well as the users so I can't create a view with just a static set of databases.
As you say you want to create view with dynamic database names - so the result you want to achieve is not possible in current versions of mysql.
So you have example following options:
Option 1
If you want to get result of all databases users tables you could define a stored procedure that uses prepared statement. This procedure needs parameter db_prefix what in your case is company_%. Basicly this procedure selects all tables named as users from information_schema when database name is like db_prefix parameter value. After that it loops through results and creates query string as union all users tables and executes this query. When creating a query string i also add field called source, so i can identify from what database this result is coming. In my example my databases are all in default collation utf8_unicode_ci.
In this case you can define procedure example "getAllUsers"
-- Dumping structure for procedure company_abc1.getAllUsers
DELIMITER //
CREATE DEFINER=`root`#`localhost` PROCEDURE `getAllUsers`(IN `db_prefix` TEXT)
DETERMINISTIC
COMMENT 'test'
BEGIN
DECLARE qStr TEXT DEFAULT '';
DECLARE cursor_VAL VARCHAR(255) DEFAULT '';
DECLARE done INTEGER DEFAULT 0;
DECLARE cursor_i CURSOR FOR SELECT DISTINCT (table_schema) FROM information_schema.tables WHERE table_name = 'users' AND table_schema LIKE db_prefix COLLATE utf8_unicode_ci;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cursor_i;
read_loop: LOOP
FETCH cursor_i INTO cursor_VAL;
IF done = 1 THEN
LEAVE read_loop;
END IF;
IF qStr != '' THEN
SET qStr = CONCAT(qStr, ' UNION ALL ');
END IF;
SET qStr = CONCAT(qStr, ' SELECT *, \'', cursor_VAL ,'\' as source FROM ', cursor_VAL, '.users');
END LOOP;
CLOSE cursor_i;
SET #qStr = qStr;
PREPARE stmt FROM #qStr;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET #qStr = NULL;
END//
DELIMITER ;
Now you can get your all users result as:
CALL getAllUsers('company_%');
In my example database it results as:
id name source
1 User 1 company_abc1
2 User 2 company_abc1
3 User 3 company_abc1
1 User 1 company_abc2
2 User 2 company_abc2
3 User 3 company_abc2
1 User 1 company_abc3
2 User 2 company_abc3
3 User 3 company_abc3
1 User 1 company_abc4
2 User 2 company_abc4
3 User 3 company_abc4
1 User 1 company_abc5
2 User 2 company_abc5
3 User 3 company_abc5
Option 2
If you really, really need view then you can modify first procedure and instead of executeing select you can create view. Example like this:
-- Dumping structure for procedure company_abc1.createAllUsersView
DELIMITER //
CREATE DEFINER=`root`#`localhost` PROCEDURE `createAllUsersView`(IN `db_prefix` TEXT)
DETERMINISTIC
COMMENT 'test'
BEGIN
DECLARE qStr TEXT DEFAULT '';
DECLARE cursor_VAL VARCHAR(255) DEFAULT '';
DECLARE done INTEGER DEFAULT 0;
DECLARE cursor_i CURSOR FOR SELECT DISTINCT (table_schema) FROM information_schema.tables WHERE table_name = 'users' AND table_schema LIKE db_prefix COLLATE utf8_unicode_ci;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cursor_i;
read_loop: LOOP
FETCH cursor_i INTO cursor_VAL;
IF done = 1 THEN
LEAVE read_loop;
END IF;
IF qStr != '' THEN
SET qStr = CONCAT(qStr, ' UNION ALL ');
END IF;
SET qStr = CONCAT(qStr, ' SELECT *, \'', cursor_VAL ,'\' as source FROM ', cursor_VAL, '.users');
END LOOP;
CLOSE cursor_i;
SET #qStr = CONCAT('CREATE OR REPLACE VIEW allUsersView AS ', qStr);
PREPARE stmt FROM #qStr;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET #qStr = NULL;
END//
DELIMITER ;
In this stored procedure we create/replace view called allUsersView, so basicly every time you will execute this procedure it will updates view.
In my test case it creates view like this:
CREATE OR REPLACE VIEW `allusersview` AS
SELECT *, 'company_abc1' as source FROM company_abc1.users
UNION ALL SELECT *, 'company_abc2' as source FROM company_abc2.users
UNION ALL SELECT *, 'company_abc3' as source FROM company_abc3.users
UNION ALL SELECT *, 'company_abc4' as source FROM company_abc4.users
UNION ALL SELECT *, 'company_abc5' as source FROM company_abc5.users ;
And now you can use view.
SELECT * FROM allusersview
And result is same as in first option.
All tested on:
Mysql 5.6.16
To find the list of database names:
SELECT SCHEMA_NAME
FROM information_schema.`SCHEMATA`
WHERE SCHEMA_NAME LIKE 'company%';
If you can code in something like PHP, the rest is pretty easy -- build a UNION of SELECTs from each database. But, if you must do it just in SQL...
To build the UNION, write a Stored Procedure. It will do the above query in a CURSOR. Inside the loop that walks through the cursor, CONCAT() a constructed SELECT onto a UNION you are building.
When the loop is finished, PREPARE and EXECUTE the constructed UNION. That will deliver something like the output example you had.
But, if you now need to INSERT the results of that into another server, you should leave the confines of the Stored Procedure and use some other language.
OK, OK, if you must stay in SQL, then you need some setup: Create a "Federated" table that connects to the other server. Now, in your SP, concatenate INSERT INTO fed_tbl in front of the UNION. Then the execute should do the entire task.
If you have trouble with the FEDERATED Engine, you may need to switch to FederatedX in MariaDB.
"The details are left as an exercise to the reader."
I already marked this as duplicate of Mysql union from multiple database tables
(SELECT *, 'abc' as COMPANY_NAME from company_abc.users)
union
(SELECT *, 'xyz' as COMPANY_NAME from company_xyz.users)
union
(SELECT *, 'company3' as COMPANY_NAME from company_company3.users)
...
I think that the only method to make this is to write a stored procedure that read all database and table name from information_schema.table, build a string with union select * from company_abc.users union all select * from company_xyz and then execute the command with prepared statement: http://dev.mysql.com/doc/refman/5.0/en/sql-syntax-prepared-statements.html
I'm looking for a way to easily check each table of a MySQL database and make sure that a certain field contains one value only. I have tables named Authors, Titles, Places, etc.
Each table contains a field called xuser and it needs to ask "does the field xuser contain the value xy in all records of all tables".
Can someone push me in the right direction how to do this with a SQL query if this is possible?
Thanks for reading, regards
Nico
I've created stored procedure which checks all table for provided db:
DELIMITER $$
DROP PROCEDURE IF EXISTS `UTL_CHECK_BACKUP_FOR_USER` $$
CREATE PROCEDURE `UTL_CHECK_BACKUP_FOR_USER`(
IN i_database_name VARCHAR(255),
IN i_user_column_name VARCHAR(255),
IN i_user_column_value VARCHAR(255),
OUT o_result TINYINT(1)
)
BEGIN
DECLARE v_table_name VARCHAR(255);
DECLARE v_last_row_fetched TINYINT(3) DEFAULT 0;
DECLARE tables_cursor CURSOR FOR
SELECT table_name
FROM information_schema.tables
WHERE table_schema = i_database_name
;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET v_last_row_fetched = 1;
SET v_last_row_fetched = 0;
OPEN tables_cursor;
SET #query =
CONCAT(
'SELECT SUM(IF(user_column=''',
i_user_column_value,
''', 1, -1)) = 1 INTO #o_result FROM ( SELECT ''test'' AS user_column FROM information_schema.tables WHERE 1<>1 '
)
;
table_loop: LOOP
FETCH tables_cursor INTO v_table_name;
IF (v_last_row_fetched = 1) THEN
LEAVE table_loop;
END IF;
SET #query =
CONCAT(
#query,
' UNION SELECT DISTINCT(',
i_user_column_name,
') AS user_column FROM ',
v_table_name
)
;
END LOOP table_loop;
CLOSE tables_cursor;
SET v_last_row_fetched=0;
SET #query =
CONCAT(
#query,
' ) all_xusers;'
)
;
PREPARE stmt FROM #query;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET o_result = COALESCE(#o_result, 0);
END $$
DELIMITER ;
Just deploy this stored procedure to database.
And then it could be executed in the following way:
-- db_name, user_column_name, user_column_value, result
call UTL_CHECK_BACKUP_FOR_USER('test', 'xuser', 'xxx', #result);
select #result;
To get the rows from all three tables where xuser has the same value in all three tables you could use:
SELECT *
FROM authors a
JOIN titles t
ON t.xuser = a.xuser
JOIN places p
ON p.xuser = t.xuser
If you want to look at a specific xuser value you could add the following WHERE clause:
WHERE a.xuser = 'xy'
The first thing comes to my mind:
select sum(if(xuser='xxx', 1, -1)) = 1
from (
select distinct(xuser) from authors
union
select distinct(xuser) from titles
union
select distinct(xuser) from places
) all_xusers;
This will return 1 (true) if all tables contains records belonging ONLY to 'xxx' user. Otherwise (if there is no 'xxx' records or there is some other user records) it will return 0 (false).
could you please give me an advice how to CALL prcd with SELECT results? Or advice me pls better solution.. I am open minded to all working solution
I have a procedure to control inserting data ...
CREATE PROCEDURE control_insert (
)
And I need to pass data from SELECT results to procedure ...
SELECT t.c1, t.c2
FROM table t1
LEFT JOIN other_table t2
ON t1.id = t2.id
WHERE 1=1
The point is, I need to get some data via SELECT (around 6 tables joined to the base table) and I need to do control for each row before insert.. each row should meet some conditions .. if it doesn't meet them, it should just skip it and process next one ...
The procedure should look like:
CREATE PROCEDURE control_insert (
IN v_c1 INT,
IN v_c2 INT
)
BEGIN
IF v_c1 > 1 THEN
INSERT INTO controlled_table (id, type) VALUES (v_c1, v_c2);
ELSE
/* do nothing */
END IF;
END;
CALL control_insert ( SELECT .... );
Could you help me with that? Is there any possibility to do this via MySQL? I can write a PERL skript, but I want to avoid this type of solution ... I just one to do it only in MySQL way
Thank you
EDIT1: I need to check if ID of the SELECT result and LABEL is already in this table for specific date ... this code above is only an example to demonstrate the situation
SOLUTION
I've found the solution ... so for the other visitors:
calling procedure:
CALL controlInsert();
procedure body:
CREATE PROCEDURE controlInsert()
BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE v_id INT;
DECLARE v_id_dupl INT;
DECLARE v_label INT;
DECLARE v_date DATE;
DECLARE v_type VARCHAR(100);
DECLARE v_category VARCHAR(255);
DECLARE v_user VARCHAR(255);
DECLARE v_country VARCHAR(255);
DECLARE c1 CURSOR FOR SELECT id, label, date, type, category, user, country FROM t1 LEFT JOIN ... /* whole select with 6 joins ended by ; */
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
## open cursor
OPEN c1;
## loop through the cursor
read_loop: LOOP
## fetch cursor into variables
FETCH c1 INTO v_id , v_label, v_date, v_type, v_category, v_user, v_country;
## check if there is any record
IF done THEN
LEAVE read_loop;
END IF;
## get count of existing records
SELECT count(*) INTO v_id_dupl
FROM
WHERE 1=1
AND id = v_id
AND label= v_label
AND date = v_date;
## if v_id_dupl = 0 => no rows found (ok to load)
IF (v_id_dupl = 0) THEN
INSERT INTO target_table (id, label, date, type, category, user, country)
VALUES (v_id , v_label, v_date, v_type, v_category, v_user, v_country);
END IF;
END LOOP;
CLOSE c1;
END
If that is all your stored procedure is doing, then you don't actually need it. You can do the whole thing in a single statement:
INSERT INTO controlled_table (id, type)
SELECT t.c1, t.c2
FROM table t1
LEFT JOIN other_table t2 ON t1.id = t2.id
WHERE something = somethingElse
AND t.c1 > 1
Essentially, I've just combined your original query with the INSERT statement in your procedure.
If your procedure is more complex and needs to do multiple operations on each row, then you should look into using a cursor.