This one really stumps me. I'm trying to create a MySQL query that I can populate information into a columns table to then export into SQLite. I can populate just about anything I want, except when the SELECT statement comes from information_schema.COLUMNS.
Here's a simple example to test. I created a table called TestTbl in a schema called and gave it 2 rows. The first is an AUTO INCREMENT INT id row, and the 2nd is a varchar 100 row called Namedb. I then run the following query.
INSERT INTO `tblinfoetc`.`testtbl` (Namedb)
SELECT
`COLUMNS`.`TABLE_SCHEMA` AS `Namedb`
FROM
`information_schema`.`COLUMNS`;
My message after doing this is:
Affected rows: 0
Time: 0.000s
If I run this without the INSERT INTO line, it returns the records without a hitch. Any ideas?
This is more of a workaround suggestion than a real solution:
Selecting from information_schema.columns works fine, so try doing the operation in two steps. First, copy the data using a client interface then insert it into the destination table from the client.
I have encountered the same problem on a windows machine running mysql 5.6.13. The query used to work with mysql 5.5. It might be related to this other issue
Related
Sorry for asking this question, but I am a beginner in SQL, my colleague at work build a view, which I need as datasource for a report, however since this view is based on several other views it takes like 45 minutes to execute the query. This is way to long. Therefore I created a table from that view, initial execution time is the same, but once in place it executes in seconds.
In Microsoft SQL Server 2014 I used the following query:
select *
into [dbo].[MAT_v_demnew_daily_am_all_data]
from [dbo].[v_demnew_daily_am]
This works fine, but since the view is updated daily I also need to refresh the table everyday. When I now execute the above mentioned query I get the message that the table already exists.
That's why I tried to use 'insert' in this case:
insert into [dbo].[MAT_v_demnew_daily_am_all_data]
select *
from [dbo].[v_demnew_daily_am]
Here I have the problem that it not only inserts the additional data but also the already existing data, so in the end I have duplicates.
As a workaround I now manually delete the [dbo].MAT_v_demnew_daily_am_all_data] table and then execute the select * into query.
Now I am looking for an easier solution, is it possible to having the table deleted by query and in the same query create a new one by select * into or is it possible to only insert new data from the view to the table so that I don't get duplicates.
Moreover, is it possible to have such SQL statement being executed automatically on a daily basis, maybe by .bat file and windows task scheduler?
I know that the source of all problems is the View and that we should improve that, but looking for a short term solution first.
Thanks so much.
Mathias
Try this:
IF OBJECT_ID('dbo.MAT_v_demnew_daily_am_all_data', 'U') IS NOT NULL
DROP TABLE dbo.MAT_v_demnew_daily_am_all_data
SELECT INTO dbo.MAT_v_demnew_daily_am_all_data FROM dbo.v_demnew_daily_am
This query is reusable on a daily basis.
You can create one stored procedure including this query.
Then you only need to execute the stored procedure.
Updated
Before you create the stored procedure, please check if you have the permission.
Then try:
create procedure [procedure_name]
as
IF OBJECT_ID('dbo.MAT_v_demnew_daily_am_all_data', 'U') IS NOT NULL
DROP TABLE dbo.MAT_v_demnew_daily_am_all_data
SELECT INTO dbo.MAT_v_demnew_daily_am_all_data FROM dbo.v_demnew_daily_am;
After you create it:
EXEC [procedure_name];
I'm having a strange issue with MySQL and database views.
I have a view defined like this:
CREATE VIEW circuits AS
(SELECT Id, Id AS Old_Id, Name FROM circuits_1)
UNION
(SELECT Id + 1000 AS Id, Id AS Old_Id, Name FROM circuits_2)
I have to join this view with a table that is in another database.
To do so, I usually prefix the table name with its database name, like db_name.table_name.
I've mapped this view using an ORM, specifying its prefix, and the resulting query is this one:
SELECT `webapp`.`circuits`.* FROM `webapp`.`circuits`
But this query returns this error:
#1051 - Unknown table 'webapp.circuits'
However, I've tried to manually run the query and remove the webapp. prefix from the SELECT statement, and it works as expected, throwing no error at all
SELECT `circuits`.* FROM `webapp`.`circuits`
Any idea why this happens?
Is it related to the way the view is defined?
EDIT
Another strange thing:
Even if this query fails:
SELECT `webapp`.`circuits`.* FROM `webapp`.`circuits`
This doesn't:
SELECT `webapp`.`circuits`.Id FROM `webapp`.`circuits`
I was hesitant to answer, as i am not familiar enough with mysql to give a full answer. I did some testing on rextester.com though, and found the following:
If I create a table test(id int), I can query it using its fully qualified object name:
SELECT rextester.test.*
FROM rextester.test
Works, no problem.
If I create a view so_test as (Select 1 id from dual)
I cannot do the same:
SELECT rextester.so_test.*
FROM rextester.so_test
Returns the same error you get.
I cannot conclude too much from this, as i don't know mysql well enough. However, it seems a general issue with views, not the way you created it.
MySQL does not seam to support * rewrite to the matching table columns with in the VIEW.
MySQL 5.6.39
http://sqlfiddle.com/#!9/68f2d3/4
MySQL 5.7
https://www.db-fiddle.com/f/taRV6FLAP6Mf8oMeuniZP3/2
MySQL 8.0.11
https://www.db-fiddle.com/f/taRV6FLAP6Mf8oMeuniZP3/3
I have trouble for my project using mysql, i want to create Auto Increment in view table, i create sintax like this one:
SELECT
concat(#AI:= #AI + 1,`code`)
FROM
`TEST TABLE`, (SELECT #AI:=0) as `AI`
Why if i add syntax in first line like this one:
CREATE VIEW `TEST VIEW` as
I have some error :
How fix it, or other method for this?. thanks for advance!
If you were using Oracle, you would use an object called a sequence for this purpose. But, who has the money for Oracle licenses?
If you need a series of numbers and you're using the MariaDB fork, you can do
SELECT seq FROM seq_0_to_99
or some such use of the SEQUENCE engine.
If you need persistent sequence numbers in MySQL, here's a workaround. It's a kludge: If you create the following table:
CREATE TABLE sequence ( /*MySQL*/
sequence_id BIGINT NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`sequence_id`)
)
Then issue these three queries one after the other:
INSERT INTO sequence () VALUES (); /*MySQL*/
DELETE FROM sequence WHERE sequence_id < LAST_INSERT_ID();
SELECT LAST_INSERT_ID() AS sequence;
The third query is guaranteed to return a unique sequence number. This guarantee holds even if you have dozens of different client programs connected to your database. (The DELETE query merely keeps this otherwise pointless table from taking up too much space.)
The error message you received makes it clear that you can't use a session variable in a view.
https://dev.mysql.com/doc/refman/5.7/en/create-view.html says:
A view definition is subject to the following restrictions:
The SELECT statement cannot refer to system variables or user-defined variables.
You can't create a view for your query. You'll have to execute the query directly. The only other suggestion I can make is to develop a stored procedure for the query.
It sounds like you want to create a row number for a query result, not an auto-increment column to store in the table.
MySQL 8.0.2 has added the window function ROW_NUMBER(), but 8.0 is still under development as we're writing this. Perhaps in 2018 it will be finished and released as GA.
I'd like to know if it is possible to create an SQL function that will automatically update my View and add to it new tables in my DB.
My DB consist of multiple tables (same data structure) and are named as follow "MM_DD", now I would like to create a VIEW that joins all this data ( pretty simple , see query below) but I wish to automate the process so every time a new table is added the view will update.
CREATE OR REPLACE VIEW `viewTable` AS
select *,
md5(CONCAT(`columnA`,`columnB`)) AS myPK_id
from `05_06`
union all
select *,
md5(CONCAT(`columnA`,`columnB`)) AS myPK_id
from `05_08`
ect...
What I am doing at the moment is using PHP every time a table is added. It loops through the tables and create / update the view.
select * from information_schema.tables WHERE table_name LIKE '%05%'
Now that I have an array of table names -> create my Query string -> replace view...
Is this possible to do this in SQL?
If so, what is the correct approach?
Write a stored procedure to rebuild your view. You'll need to use what MySQL internally calls "prepared statements" so you can use string manipulation.
You'll still use your SELECT ... FROM information_schema.tables query to drive this stored procedure.
Once you get this working, you can embed it in a mySQL event, and arrange to run it automatically. For example, you could run it at the same time late at night.
Or, you can invoke the stored procedure immediately after you create one of these tables.
After executing the following code:
SELECT
industry,
company,
GROUP_CONCAT(symbol SEPARATOR ',') AS symbol
FROM
table1
GROUP BY
SOUNDEX(company),
I managed to merge some rows, however the table isn't updating itself with the merged rows and cells.
I then tried using UPDATE / SET / WHERE but not quite sure what to SET and WHERE as I need to update every merged row/cell. The "best error" that I get is Operand should contain 1 column(s)
I'm now quite stuck here.. any hint at how to update the table would be much appreciated.
EDITED
Some more details:
I'm making a PHP code that can feed data from xml to database, then look for duplicate entries and merge it like this:
here is the snapshot of my DB table:
When I run code above code through PHP - there are no changes to the above DB table
But when the code is executed directly in phpMyAdmin "SQL", the following changes can be seen:
But when I click back to "Browse", all data stays as it was.
Thus it let me think that it is not updating after I did merging...