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
2answers
489 views

Check and Retrieve those results where a cell(row) contains atleast one value from many values in a column [duplicate]

Let me give you an example : I have a table (name = posts) which contains following rows: id | title | .... | names 1 | . | . | . | . | . | 4 ...
16
votes
2answers
33k views

How do I shrink the innodb file ibdata1 without dumping all databases?

InnoDB stores all tables in one big file ibdata1. After dropping a big table, the file is keeping its size no matter how big the table was. How can I shrink that file without having to dump and ...
0
votes
0answers
1k views

Openquery insert not working

I have a linked MySQL -server to MSSQL-server and I am trying to INSERT data to the table admin_user on the MySQL -server, but end up getting the error: annot process the object "dbo.admin_user". ...
1
vote
2answers
923 views

Is there any manual for the visual explain in mysql? The output plan is unreadable

Just like this example, I cannot even tell the join ordering from it. And what does "ALL" and "ref" in the table mean? Is there any manual about the visual explain?
1
vote
1answer
772 views

Best backup strategy for MySQL (MariaDB) replication set

My main concern is getting a proper backup, even more so than a temporary outage. The data is golden. I've been doing reading through the documentation and a lot of the backup strategies seem to be. ...
1
vote
2answers
12k views

Foreign Key Constraint fails

I have the following tables: // Base Scans CREATE TABLE `basescans` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `name` VARCHAR(100) NULL DEFAULT NULL, `status_id` INT(10) UNSIGNED ...
1
vote
2answers
511 views

MySQL : 30GB of binlogs in 6 Hours

I have a mysql master/master setup with tungsten replicator. My server is reaching out of space, occupied around 30G in 6 hours. I'm not sure how to handle this. Would be great if some one can help me ...
0
votes
0answers
178 views

MySql query, 3 tables join takes 10+ sec

I need help refactoring this query, it joins 3 tables and subquery 4th. Order by should be possible by selected fields from 3 tables. t1 has 70k rows t2 has 20 rows t3 has 10 rows post_cc about 1500 ...
3
votes
1answer
83 views

Doing a join to search geolocation points in zones

I have a series of geolocation points in a table, and a series of "zones" in another; I'd like to do a join to identify which zone each point belongs in (if at all.) Points table looks like: ...
0
votes
2answers
525 views

MySQL stored procedure create database by month

I'm a systems admin, and I'm not a dba, I'm wondering if I could use MySQL stored procedure to Query main database and move records by month to another database located on the same system. This ...
1
vote
1answer
129 views

How would I exclude a group of tables based on a name prefix foo_* from a mysqldump?

I'd like to exclude a group of tables from a mysqldump command (from a bash script). I might not know the exact table names ahead of time but they will be named with the prefix foo_ or might contain ...
12
votes
3answers
8k views

How to convert mysql to postgresql? [closed]

I am desperately looking for a conversion tool to convert a big mysql database to postgresql. I need the tool/script to be: Free Works under Linux Simple to use and not buggy You actually tried and ...
1
vote
2answers
108 views

how should i do this trigger?

I am a newbie to the sql world :) Right now i'm trying to create my first mysql trigger that would either update a row or insert a new one. Could you help me with that ? Here is the code : DELIMITER ...
1
vote
1answer
978 views

temp table (#sql-7a87_230c32.ibd along with its .frm) still exists on slave

I executed some alter statements on my master server, which have been successfully executed on master (now there is no temp table on master) and all alter also have been replicated on slave server ...
0
votes
0answers
487 views

How to skip already created table while importing dump file in MySql

Is there any way to skip already created tables while importing ? I am trying to import 2GB of database using command prompt but the operation is aborted by mistake. Now if i will do the import again ...
0
votes
1answer
165 views

Need some expert eyes to look at my schema

I am trying to make an online site for local movies. Will be written in PHP and will be using MySQL as the database. What I want is to create a mini IMDB type site, with movies, people(casts/crew), ...
2
votes
1answer
375 views

MySQL cluster DataMemory and DiskPageBufferMemory parameters

I want to setup a MySQL cluster. The amount of data is more than double the amount of RAM. I have 3 Data Nodes each with 8GB RAM. QUESTIONS What is a good rule for the DataMemory and ...
2
votes
0answers
76 views

Denormalizing to speed up inserts

I have a MySQL InnoDb table with approximately 40 million rows and the following columns: param1 (int), param2 (int), param3 (int), geo (char2), value1 (bigint), value2 (bigint) I have an ...
0
votes
1answer
703 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
265 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
213 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
606 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
327 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
561 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
261 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
638 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
864 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
498 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
677 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 ...