All versions of MySQL (not Microsoft SQL Server). Please also add a version-specific tag like mysql-5.7 if that is relevant to the question.

learn more… | top users | synonyms

0
votes
1answer
711 views

MySQL - How to select rows until condition is met

I have a table that has a numeric field (call it NUM), I want to select rows until the sum of all NUM selected reaches some threshold. Is there an efficient way to do this?
1
vote
2answers
267 views

MySQL 5.5 to 5.6 Upgrade. Will data remain the same?

We are considering to upgrade to MySQL 5.6 this summer. I would like to know if our data will be changed in any way once we perform the upgrade? I've been reading and I found that mysql_upgrade ...
20
votes
6answers
2k views

Count where two or more columns in a row are over a certain value [basketball, double double, triple double]

I play a basketball game which allows to output its statistics as a database file, so one can calculate statistics from it that are not implemented in the game. So far I've had no problem caluclating ...
1
vote
1answer
216 views

Slow queries InnoDB occasionaly

I have the next table: CREATE TABLE `sessions` ( `session_id` char(32) COLLATE utf8_unicode_ci NOT NULL, `session_expires` int(11) NOT NULL DEFAULT '0', `session_data` varchar(10000) COLLATE ...
1
vote
4answers
131 views

Amount of data in a database table

I am trying to run an alter query on a table, and its giving me a Lost connection to MySQL server during query MySQL server has gone away. The query that I am running is alter table table_name ...
2
votes
1answer
92 views

Can't figure out this “trick” to optimize MySQL query

Here's an excerpt of this article: SELECT id, name, address, phone FROM customers ORDER BY name LIMIT 10 OFFSET 990; MySQL is first scanning an index then retrieving rows in the table by ...
1
vote
2answers
125 views

how to use an index on a mysql query with a where clause and a order by

I have a table CREATE TABLE activity ( id INT(10) UNSIGNED AUTO_INCREMENT, subscriberid INT(10) UNSIGNED NOT NULL DEFAULT '0', action VARCHAR(250) NOT NULL DEFAULT '', ip INT(10) UNSIGNED NOT ...
0
votes
0answers
608 views

Using a `mysql_query` to insert category values

Ok I'm importing direct from a csv to MySQL, using a mysql_query to insert values. How do you insert category terms into the Wordpress database structure assigning them to a post. Below are two import ...
0
votes
0answers
332 views

MySQL my.cnf File Optimization help

I need help for Optimizing my MySQL Server for my Dedicated server with configuration of Intel Core 2 Duo CPU E7500 @ 2.93GHz 4GB of RAM installed. OS installed is CentOS 6.5. Mostly on my Dedicated ...
3
votes
1answer
565 views

mysqldump freezing on a specific table

I dumped a database (sys_data) which is very big (800GB, all data in one ibdata file) from a remote server. But the dump was blocked at a table (tb_trade_376). My dump command: mysqldump -uxx -pxx ...
1
vote
1answer
27 views

is there any need to index b again as it is already a under primary

Is there any need to index b again as it is already a under primary- if primary(a,b) and in query we have where b=' '; Is there any need to index(b) again individually because while indexing it ...
0
votes
0answers
80 views

mysql logs same query multiple times or is it application problem?

I have temporarily switched on logging on the server. The site is used in the US and local time there was 4 in the morning so not many people are using it at that time. What I did was delete any logs ...
2
votes
2answers
262 views

MySQL nested queries

I'm working on a project using a MySQL database and we'd like to combine a query which was previously made in several steps into one step. The queries are created in a Java-App using Hibernate. Goal ...
1
vote
1answer
9k views

How to insert data into tables which reference each other?(MySQL)

I'm a student and right now I have a problem that I couldn't solve by myself(after searching on the Internet). I'm not going to give my «homework» because I want to learn what I'm doing but I will ...
0
votes
1answer
36 views

MySQL Identifying Connection Attempt

I'm seeing the following errors repeatedly in the error log file for our production MySQL server: [Warning] Access denied for user 'root'@'remote.appserver.com' (using password: NO) So, I know ...
0
votes
0answers
13 views

mysql - innodb - crashed - mysql cannot start - please help asap! :) [duplicate]

I am having a major crash on mysql affecting a lot of websites. We had a crash on our SAN storage. Since that time, mysql refuse to start. I tried to reinstall mysql, but still no luck. I think ...
0
votes
0answers
16 views

Users_With_Messages Table normal form

I have the following tables in my database: Above these tables (not pictured) is a Users table where the SendingUserId and ReceivingUserId are keyed onto (they are foreign keys). Are these tables ...
1
vote
0answers
1k views

Error when syncing MySQL database (XAMPP) on Dropbox

I'm working on a MySQL database for local development using XAMPP, and I would like to work on two different computers. Looking online, I saw this link that gives a tutorial on syncing your database ...
3
votes
1answer
1k views

fetching externally hosted db's table from within the local mysql server

Let's say we have a mysql database on localhost with table A and table B. Is it possible to fetch details from a 3rd party mysql server to which we have login info and which allows external access? ...
4
votes
1answer
643 views

When interrupting a query on a Master, does it replicate to the Slave?

In MySQL, when does the master send a query to the slaves? Here's a specific scenario that I'm trying to understand. Admin entered an update on master that took a long time to execute. Admin hits ...
0
votes
1answer
33 views

MySQL still seems to be establishing a connection even when access is denied, causing aborted connects and instability

Lately the server's been going a bit haywire and we've spent several weeks chasing down leads to no avail. All we can tell is that when the websites go down (and come back up, and go down, and come ...
0
votes
1answer
56 views

How to optimise very simple query with subquery that only needs to execute once

SELECT products_id, products_model, products_iban_no, products_allocation_number FROM products WHERE products_model IN (SELECT products_model FROM products GROUP BY products_model HAVING ...
0
votes
1answer
866 views

Split MySql table into two tables with One to many Relationship

I have an old database table in MySql. It is used to store the orders from online ecommerce. Simplified diagram looks like this: +----+------+-----------------------+-------+--------------+ | id | ...
1
vote
2answers
499 views

MySQL5.6 on Mac OS X 10.6.8 problems when granting permissions to root

I'm having serious problems with a MySQL 5.6 instance on a Mac Server. We had to upgrade MySQL to a newer version, but it turned to be a bad idea, as we lost control to it. We had a backup of the ...
1
vote
0answers
37 views

How to update all primary keys in the existing database

I'm moving mysql multi-master replication to production using tungsten. I had setup the auto increment and offset values in my.cnf file. To achieve this i'll have to update my all primary keys of all ...
3
votes
2answers
1k views

Can I move the undo log outside of ibdata1 in MySQL 5.6 on an existing server?

I've been growing concerned about the large size of ibdata1 that can never shrink even when using file-per-table on innodb Moving the undo log files outside seemed logical but this procedure seems ...
1
vote
2answers
4k views

Only “grant usage”, but can still select, drop, create?

I have a mysql user (I'll call) "user5" who only has "grant usage" (i.e. no privileges) in the output of "show grants", but can still do a select on database "app_db" (which is what I want, but I do ...
1
vote
1answer
252 views

percona xtrabackup to backup mysql database

I'm trying to use percona xtrabackup to backup a mysql database. in the restoring the database according to the documentation: rsync -avrP /data/backup/ /var/lib/mysql/ this will copy the ibdata1 ...
0
votes
0answers
45 views

Normalization of irregular relations?

I have two tables in MySQL: The orders table CREATE TABLE `orders` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `transaction_id` varchar(20) COLLATE utf8_unicode_ci DEFAULT NULL, `task_id` ...
1
vote
2answers
680 views

Mysql Connection Pooling Similar To PostgreSQL's PgBouncer

I'm looking for a pooling solution for mysql that is independent of the language. I am using PGBouncer as an example because it Resides on the server the database is on Just change the connection ...
1
vote
1answer
3k views

What is the Best Way to detect if server is a Master inside a Stored Procedure?

I'm want to create a stored procedure/event to do some maintenance tasks. My setups are master/slave configured for failover scenarios (meaning the slave is not used for reporting, just might be ...
6
votes
2answers
4k views

MySQL Locks while CREATE TABLE AS SELECT

I am running the following (dummy) query CREATE TABLE large_temp_table AS SELECT a.*, b.*, c.* FROM a LEFT JOIN b ON a.foo = b.foo LEFT JOIN c ON a.bar = c.bar Suppose the query ...
3
votes
1answer
4k views

mysql table very large size although it doesn't have a lot of records

I have drupal website, one of the tables is cache_form. I have a cron to DELETE FROM cache_form where expire < UNIX_TIMESTAMP(NOW()); which works fine. The size of cache_form.myd is 4.9G ...
0
votes
1answer
425 views

Unable to migrate local database to RDS instance

I recently created an MySQL instance on Amazon RDS. Unfortunately, I'm not able to connect to the instance from the MySQL command line. I will brief you the details. 1) I want to move/migrate my ...
1
vote
2answers
546 views

MySQL Database replication for high availability

configuration: 1 balancer 2 Azure machines(4 gb ram, 2 cores), with MySQL master-master replication enabled. X users connecting to the balancer to sync data. test: i've tested the MySQL ...
2
votes
1answer
1k views

Is there a product to auto-build indexes based on slow queries?

I'm looking to either find, purchase, or write a script to identify slow queries, identify potential missing indexes, and when needed create the appropriate index within a reasonable amount of time of ...
0
votes
1answer
100 views

Column to Row and Vice Versa

I need to create a new table by combining the contents of two different tables. Is there any way to transform columns into rows and rows into columns in MySQL? I tried using JOIN but I can't seem to ...
0
votes
1answer
5k views

Find the size of each index in a MySQL table

I am trying to figure out size of each index of a table. SHOW TABLE STATUS gives "Index_length" is the summation of all the indices of the table. However if a table has multiple indices (e.g. in an ...
1
vote
0answers
4k views

getting SQL Error (1452): Cannot add or update a child row: a foreign key constraint fails (Unknown error code)

I am getting error with MySQL NDB Cluster 7.3.5 as described below: I have two tables: -User Profiles -User Services User services is a child table which contains foreign key constraint ...
2
votes
1answer
307 views

Why am I getting different results from a query vs. a view

The base problem I'm facing is that I need the latest record for each item. A little setup... MySQL 5.6.14. I need to create two views (because MySQL won't let me have a subquery in a view). My ...
2
votes
1answer
7k views

Aborted connection (Got an error reading communication packets) MySQL on Amazon RDS

I'm getting the following warning in MySQL: Aborted connection (Got an error reading communication packets) I'm using Amazon RDS for MySQL hosting. Both MyISAM and InnoDB storage engines are ...
0
votes
1answer
102 views

How To Prevent Replication Failure

If I become a MySQL DBA, will I had to deal all day with those kind of issues or do you have tips to prevent from breaking the whole replication? I received this message because I removed manually ...
1
vote
1answer
89 views

MySQL from table to table data transfer

I've got some problem with my MySQL. I have the database with many many data. Well, there is only one table actually with huge ammount of data, over 1 billion rows. For some reasons I need to create ...
1
vote
1answer
25 views

CREATE TABLE not issued on other masters

Database is created on all multi masters. Why CREATE TABLE doesn't being replicated to other masters. some explanations?
0
votes
0answers
154 views

CREATE VIEW joining two tables, only displaying rows from the first table with the most recent date in the second table

I have multiple tables. My main table has a composite key consisting of a phone number and an order number. I want to create a VIEW where only the subscriptions with the most recent order date are ...
1
vote
3answers
5k views

Is there a free software that can import excel into mysql on mac? [closed]

not csv format files, but .xls or .xlsx format excel files, is there any free software for mac, that can import data into mysql?
0
votes
1answer
91 views

MySQL - Bin folder [closed]

I'm trying to learn all the binary files inside the mysql bin folder,but unfortunately I couldn't able to find the detailed explanation of these.So please tell me the procedure to have good knowledge ...
0
votes
0answers
71 views

Upgrading MySql 5.1 to MySql 5.5

I followed a tutorial to update My MySql 5.1 to 5.5 (actually i wanted to upgrade to 5.6, but the tutorial mentioned that i should upgrade to 5.5 first and then to 5.6). However, after removing ...
1
vote
0answers
224 views

Match unique id's on import- csv to sql

I have a csv file that I would like to import into a phpMyAdmin database (Wordpress). The CSV file is formatted as shown below: list-id | post_title | slider | ...
0
votes
0answers
245 views

Upgrading MySql 5.1 to MySql 5.5

I followed a tutorial to update My MySql 5.1 to 5.5 (actually i wanted to upgrade to 5.6, but the tutorial mentioned that i should upgrade to 5.5 first and then to 5.6). However, after removing ...