Re: Query optimizer-miss with unqualified expressions, bug or feature?

[Johan De Meersman]

- Original Message -
> From: "Shawn Green" 
> Subject: Re: Query optimizer-miss with unqualified expressions, bug or 
> feature?
> 
> On a more serious note, indexes with limited cardinality are less useful
> than those with excellent cardinality. Cardinality is an approximation
> (or calculation. It depends on your storage engine) of how many unique
> values there are in the index.

On a related note, are there any plans (and could you offer a rough timeframe?) 
to include bitmap indices in MySQL?


Thanks,
Johan

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Re: Query Help...

[Peter Brawley]

On 2015-10-20 12:54 PM, Don Wieland wrote:

Hi all,

Trying to get a query working:

SELECT
ht.*,
CONCAT(o.first_name, " ", o.last_name) AS orphan,
GROUP_CONCAT(DISTINCT hti.rec_code ORDER BY hti.rec_code ASC SEPARATOR ", ") AS 
alloc

FROM hiv_transactions ht

LEFT JOIN tk_orphans o ON ht.orphan_id = o.orphan_id
LEFT JOIN hiv_trans_items hti ON ht.transaction_id = hti.hiv_transaction_id

WHERE ht.donor_id = 730 AND ht.tr _date BETWEEN "2014-01-01 00:00:00" AND 
"2014-12-31 23:59:59"
ORDER BY ht.tr _date DESC, ht.rec_code ASC;



I am only showing one row of the “hiv_transactions” table when there are 
multiple rows.

On the GROUP_CONCAT I am trying to get a comma delineated list of the child 
rec_code with no duplicates

Appreciate any help. Hopefully a small mod ;-)


Group_Concat() is an aggregating function, so you need to Group By the 
column(s) on which you wish to aggregate, and for valid results you need 
to limit Selected columns to those on which you're aggregating plus 
those columns that have unique values for your aggregating columns..


PB





Don Wieland
D W   D a t a



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Query Help...

[Don Wieland]

Hi all,

Trying to get a query working:

SELECT 
ht.*, 
CONCAT(o.first_name, " ", o.last_name) AS orphan, 
GROUP_CONCAT(DISTINCT hti.rec_code ORDER BY hti.rec_code ASC SEPARATOR ", ") AS 
alloc 

FROM hiv_transactions ht 

LEFT JOIN tk_orphans o ON ht.orphan_id = o.orphan_id 
LEFT JOIN hiv_trans_items hti ON ht.transaction_id = hti.hiv_transaction_id 

WHERE ht.donor_id = 730 AND ht.tr _date BETWEEN "2014-01-01 
00:00:00" AND "2014-12-31 23:59:59" 
ORDER BY ht.tr _date DESC, ht.rec_code ASC;



I am only showing one row of the “hiv_transactions” table when there are 
multiple rows.

On the GROUP_CONCAT I am trying to get a comma delineated list of the child 
rec_code with no duplicates

Appreciate any help. Hopefully a small mod ;-)


Don Wieland
D W   D a t a  

Re: Query Help...

[shawn l.green]

On 10/20/2015 1:54 PM, Don Wieland wrote:

Hi all,

Trying to get a query working:

SELECT
ht.*,
CONCAT(o.first_name, " ", o.last_name) AS orphan,
GROUP_CONCAT(DISTINCT hti.rec_code ORDER BY hti.rec_code ASC SEPARATOR ", ") AS 
alloc

FROM hiv_transactions ht

LEFT JOIN tk_orphans o ON ht.orphan_id = o.orphan_id
LEFT JOIN hiv_trans_items hti ON ht.transaction_id = hti.hiv_transaction_id

WHERE ht.donor_id = 730 AND ht.tr_date BETWEEN "2014-01-01 00:00:00" AND "2014-12-31 
23:59:59"
ORDER BY ht.tr_date DESC, ht.rec_code ASC;



I am only showing one row of the “hiv_transactions” table when there are 
multiple rows.

On the GROUP_CONCAT I am trying to get a comma delineated list of the child 
rec_code with no duplicates

Appreciate any help. Hopefully a small mod ;-)


Don Wieland



Which release of MySQL are you using?

How many rows do you get if you remove the GROUP_CONCAT operator? We 
don't need to see the results. (sometimes it is a good idea to look at 
the raw, unprocessed results)


Is it possible that you are attempting to concat more values than 
allowed by --group-concat-max-len ?


Yours,
--
Shawn Green
MySQL Senior Principal Technical Support Engineer
Oracle USA, Inc. - Integrated Cloud Applications & Platform Services
Office: Blountville, TN

Become certified in MySQL! Visit https://www.mysql.com/certification/ 
for details.


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MySQL Connector/NET 6.9.8 has been released

[karen langford]

Dear MySQL users,

MySQL Connector/Net 6.9.8 is a maintenance release for the 6.9.x
series of the .NET driver for MySQL. It can be used for production
environments.

It is appropriate for use with MySQL server versions 5.5-5.7.

It is now available in source and binary form from
http://dev.mysql.com/downloads/connector/net/#downloadsandmirrorsites
(note that not all mirror sites may be up to date at this point-if you
can't find this version on some mirror, please try again later or choose
another download site.)

Changes in MySQL Connector/Net 6.9.8 (2015-10-20)

   Functionality Added or Changed

 * The GB18030 Chinese character set is now supported, a
   character set that was added in MySQL 5.7.4. (Bug
   #21098546, Bug #21803306, Bug #21803300)

 * Generated columns (GENERATION_EXPRESSION) are now
   supported, a feature added in MySQL 5.7.6.

 * The JSON type is now supported, a type that was added in
   MySQL 5.7.8.


The documentation is available at:
http://dev.mysql.com/doc/connector-net/en/

Nuget packages are available at:
https://www.nuget.org/packages/MySql.Data/6.9.8
https://www.nuget.org/packages/MySql.Data.Entity/6.9.8
https://www.nuget.org/packages/MySql.Fabric/6.9.8
https://www.nuget.org/packages/MySql.Web/6.9.8


Enjoy and thanks for the support!

On behalf of the MySQL Connector/NET and the MySQL/ORACLE RE Team.


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