MySQL : Open-Source, Relational Database Management System

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MySql – Get comma separated values from a table, should not exist in another table

I have two tables, table structures as below. Table: items Id item_name item_ids 1 pens 10,11,12,13 2 books 20, 30 3 computer 50, 60, 80 Another table : ...
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1answer
2k views

Extract MySQL information from a compressed tar.gz file

I have a back up-of a MySQL database which is contained in a .tar.gz file - I need to restore it. I've never had to do this before. The only way I can access the database is through phpmyadmin. There ...
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15 views

MySql GROUP BY on two large joined tables

I have two tables: Person PersonID (PK) GroupID DeletedDate PersonData PersonID (PK) FieldID (PK) Value The fields are custom-created; hence the schema. I am trying to run a histogram-type query to ...
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7 views

Prevent Reconnections During Application Cluster Restart

I have a large cluster of application processes (>5000) spread out over multiple EC2 servers. When I attempt to restart them or deploy new code (with a restart), they all attempt to reconnect to the ...
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1answer
16 views

InnoDB row metadata size (minimum row size)

I'm trying to decide whether to normalize a thing further, and need to know what the smallest a row in InnoDB can be (I've got MySQL 5.6). This is not exactly my case, but for simplicity, let's ...
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50 views

Can queries containing deterministic user defined functions be cached in mysql query cache?

According to the mysql 5.6 docs: A query also is not cached under these conditions: ... It refers to user-defined functions (UDFs) or stored functions. However, I have seen claims that if ...
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16 views

SELECT that is null if there is one more register in this date that is not null

I'm trying to make a query that I can't produce... This is my table capturainfo captureid int(11) userid int(11) date date dateinit datetime datefin datetime I need to select ...
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3 views

MySQL ALTER TABLE table_name AUTO_INCREMENT=1 doesn't work

I'm using yii and it's test system. Yii's fixture manager resets tables and their AI keys so: DELETE FROM table_name; ALTER TABLE table_name AUTO_INCREMENT = 1; It was working good on server before ...
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126 views

How do I find duplicate values in multiple columns over different rows?

I have a database with a table of games (some columns omitted): gameid hometeam awayteam `date` Sometimes games are added with the same home and away teams, but on a different date that is just 1 ...
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19 views

SQL error: Unknown column in 'where clause'

I have following very simple PHP MySQL Query: $sql = 'SELECT * FROM bundesland WHERE bkuerzel = ' . $_GET['q']; $result = mysql_query($sql, $con); When I execute the query with a click on a item ...
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828 views

mysqlcheck --repair a specific table?

I logged in my server via SSH and committed a "repair table xxx" query on a MyISAM table with 34 million rows and 69GB of data. Unfortunately the SSH connection was lost. When I logged back in I found ...
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Query error int/varchar LEFTJOIN [on hold]

Can someone tell me what´s wrong with this query? $sql = "select bans.id as banid, bans.type, bans.data, bans.reason, bans.expire, bans.added_by, bans.added_date, players.id as playerid, ...
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133 views

InnoDB Failure of some kind

I have MySQL 5.5 installed. I tried to install Joolma but it failed. I went into their sql and replace EGNINE=InnoDB with MyISAM and the install worked. InnoDB is listed under SHOW ENGINES; Any idea ...
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1answer
13 views

MySQL - Changing from system tablespace to file per table

The MySQL database I am working on has the InnoDB tables and indexes stored in the system tablespace which is now > 20Gb. Some years ago I managed a MySQL database that made use of a file per table ...
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4answers
33 views

Remote MySQL connection fails (10060) - “Can't connect to MySQL server on domainname.com(10060)”

I have developed one application in vb6, and i am using online MySQL database server for storing my application's data. So when i am try to connect with my database server,when first time i connect to ...
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2answers
51 views

How to speed up mysql export and import

I need to perform a DB migration from Server A to Server B. Server A: MySQL version installed 5.0.6 Server B: MySQL version installed 5.6.20 OS: Both are running RedHat Linux 64bit. 16 ...
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22 views

Big difference between id value [duplicate]

I have this database table where I insert multiple results during 1 action. In php I have a submit button when pressed, inserts 1-50 rows(depending on the user input). I've got a foreign key in this ...
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2answers
32 views

How can I use 'system pwd' command with MySql CONCAT() function?

How can I use 'system pwd' command with MySql CONCAT() function? I tried select concat('test', system pwd); gives me ERROR 1583 (42000): Incorrect parameters in the call to native function ...
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1answer
414 views

MySQL slave taking too long on “Queueing master event to the relay log”

I have two mysql mysql slave servers. The DB version is: mysql> show variables like '%version%'; +-------------------------+-----------------------------------------------------+ | Variable_name ...
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1answer
87 views

MySQL dump - how to order tables?

It seems that mysqldump dumps tables in sequential order - using the same order tables are shown when running: show tables; I would like to reverse that order - is it possible to do without getting ...
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2answers
5 views

How does InnoDB access disk?

I know that block(multiple disk sectors) is the basic unit of data transfer for the virtual file system so, if NTFS uses 4 KB cluster size for files how does InnoDB access disk if it uses 8 KB page ...
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102 views

#1025 - Error on rename of table errno: 150 : Table was deleted while tried to assign foreign key

When I tried to assign foreign key to a table named mydb.table1 it was deleted from my database, I could not understand the reason and tried to move on. For this tried to create same table with create ...
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3answers
99 views

Question on having a MySQL 5.1 replicate from a MySQL 5.6 DB

I have a question in regards of what potential issues that might happen with a MySQL 5.1 DB that replicates from a MySQL 5.6 DB. I know the risks involved based on resources such as ...
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1answer
460 views

Issue when connecting to open shift via mysql workbench on Mac

I am trying to connect to open shift with mysql workbench on an iMac. A colleague has shown me his setup on Windows which looks exactly as follows (other than the usernames / passwords changing) ...
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162 views

MySQL 1264 warning from libmysql

I'm using the libmysql.dll library to connect to my database from a 3rd party application (metatrader). I managed to connect and things are going almost fine. I use mysql_real_connect and ...
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1answer
104 views

Remove question marks from database(latin1_general_ci table)?

How can I remove question marks(not diamond shaped) from a latin1_general_ci MyISAM table? I tried going back to utf8 and tried to apply things in ...
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20 views

I cant find compiled versio of mydumber for mysql backup in windows [on hold]

I cant find mydumper (compiled) for windows, please dont address me for not compiled for windows . thanks
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1answer
168 views

Quickly establishing if a remote MySQL connection is valid using PHP

I have a hosted website (Namecheap Pro shared hosting) that connects to a remote MySQL database using a read-only user privilege. This remote DB is updated by a separate system. The website works ...
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1answer
30 views

Database Design Question? Relationships and Form Data

I am working on a project that requires to store evaluation form data. Essentially, the a reviewer will fill out a form based on the performance of the person being evaluated. Now there is well over ...
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1answer
11 views

list of items or menu in mysql workbench

i am creating a database for an android tourism app. i am working on MySQL workbench, i want to create a menu in my database, for example i want to list the cities of my country, or list the ...
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22 views

11.2GB text file import MySQL or PostgreSQL

I am out of my depth a bit perhaps but submit this query hoping someone has some experience importing large (11.2GB) tab delimited text file (2.2GB tar.gz file) into either MySQL 5.5.41 or PostgreSQL ...
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1answer
1k views

MySQL error 2006 MySQL server has gone away after upgrade to 5.6.10 using homebrew on Max OS X 10.8.3

I upgraded my installation of MySQL on my Mac OS X 10.8.3 using homebrew brew install mysql Everything seemed to go smoothly, but...not really, as it turns out. I cannot add a new user (neither ...
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443 views

Import CSV file into Mysql with Multiple Delimiters/Field Separators

I'm trying to import a large csv file into Mysql. Unfortunately, the data within the file is separated both by spaces and tabs. As a result, whenever I load the data into my table, I end up with ...
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2answers
702 views

To what extent is MariaDB Java client a perfect replacement for MySQL JDBC (Connector/J)?

Premise: I ship a Java application which will make a JDBC connection to a MySQL database. (At the time of this writing it could be 5.1 or 5.5, but hopefully the question and answer don't rely heavily ...
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3answers
678 views

Why would I use the MySQL “system” command?

What can I do with the MySQL client's system command? Why does it exist? The most productive use I've seen is to look around the file system (e.g., to remember the file name you want to SOURCE or ...
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Mysql 5.5.25 must be restarted to connect

We have MySQL v5.5.25 running on Windows Server 2008 R2. Occasionally people are unable to connect, and the only way we have found to fix this is to restart the mysql service. This happens every 2-3 ...
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3answers
4k views

Mysql backup strategies?

We have a innodb mysql database so we are lost with lots of different mysql backup strategies. Some talk about mysqldump some talk about third part tools. Some of the tables we also plan to run ...
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1k views

Importing a SQL Dump File through XAMPP's Command Line

A few days ago, I exported a .SQL dump file with all my databases, which is about 150MB. The thing is I cannot import it through phpMyAdmin since the file is way to big. I remembered there was ...
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441 views

ON creating BITMAP INDEX on a table in mysql throws error

say, i have database named "demo_dev" database and added a table named "countries". i wanted to create bitmap index on a column say region as it has less unique values using following query. CREATE ...
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1answer
41 views

query slows down exponentially as table grows

I have the following query running on mysql 5.6 on my CENTOS server select tb1.field2, tb1.field1, tb2.field1 from dns.table1 tb1, dns.table2 tb2 where tb1.field2 = tb2.field2 and tb1.field1 != ...
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1answer
19 views

All users are having NO Privileges in phpMyAdmin

By mistake, I changed all the privileges of user 'root' in my MySQL Database. Not even a single privilege is having for that user. Now if I log in with another user I am able to access only one ...
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1answer
104 views

Reviewing relational database tables

I am building a database, but I am a little bit confused with my table relationships. I wish someone could help review my table relationships below for me and tell me where I am going wrong. I have ...
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1answer
472 views

Calculating the median value in a MySQL table with CodeIgniter

This is my model file in codeigniter. I need to calculate the median for this variable: budget_breakdown.breakdown_grants. How can I do this calculation? function reports_details1() { ...
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3answers
43 views

How do I do an outer join between all nested subqueries? (getting an error of 'OUTER' is not a valid input for this position) [on hold]

I have this query: SELECT AVG(a.score) AS Average1, AVG(b.score) AS Average2, AVG(c.score) AS Average3 FROM (SELECT subfactor.score, dateID, EmployeeID FROM employeescore LEFT JOIN ...
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MySQL 5.1.73-cll and engine MyISAM PRO AND CONS FOR THE FOLLOWING 2 'DELETE' APPROACHES [on hold]

For MySQL 5.1.73-cll and engine MyISAM what are the pros and cons for the following two possibilities of 'deleting' rows(let's say that a user want's to delete his profile/delete some of his products ...
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3k views

Select from a list of values from JSON encoded data

I have saved the details of the product in JSON format. I am wondering how to select from a list of values from a "JSON_ENCODED DATA" For Example I want to select TV with screen_type as LED or LCD. ...
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2answers
166 views

ib_logfile opened with O_SYNC when innodb_flush_method=O_DSYNC

mysql will open and flush data/log files as below when innodb_flush_method=O_DSYNC Open log Flush log Open datafile Flush data O_SYNC NONE NONE fsync () ...
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1answer
30 views

Combining multiple rows into single column

The return from my MySQL statement displays an example below: id 1 | status | id 2 | name | category 001 | open | 011 | john | person 001 | open | 011 | john | male How would I combine the ...
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2answers
151 views

Dealing with data stored as arrays in a MySQL DB

So I know storing arrays in a DB field is wrong and would never do it myself, however a 3rd party plugin my company is using stores data in an array and I was wondering if you could help me try to ...
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2answers
263 views

Mysql trigger not working, syntax issues

I have this trigger CREATE TRIGGER checkcollision AFTER UPDATE ON players BEGIN SELECT RAISE(ABORT, 'collision') FROM walls WHERE NEW.x=x AND NEW.y=y; END; mysql 5.1.72-0ubuntu0.10.04.1 ...