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.

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0
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1answer
624 views

Use string functions and arithmetic calculations in SQL query or by programming language?

I need heavy arithmetic and string functions for processing the data captured from mysql database. Which is preferred: mysql functions or programming language (e.g., PHP)? $result = ...
2
votes
1answer
487 views

Need to suppress rowcount headers when using \G

Is there a command to suppress the rowcount headers and asterisks when using '\G' to execute a SQL statement? I am executing mysql with the -s and --skip-column-name options, but these don't suppress ...
1
vote
1answer
1k views

Mysql Innodb as Key value store, performance

I read about NoSQL databases using Key value pairs (KVP) tables. So i wanted to find out if KVP tables would be faster than conventional relational tables (with multiple columns) in mysql with innodb ...
0
votes
1answer
145 views

How can I normalize this database?

I've got legacy ecommerce database, which is awfully designed and I need to move all products from it to new solution. But I stuck with how product properties stored. So it basically has tens of ...
0
votes
0answers
153 views

Overcoming the HDD IOPS limits on a billion row table? Is getting SSD the only solution?

I have a table with this structure: CREATE TABLE `requests` ( `userid` int(11) NOT NULL, `messageid` int(11) NOT NULL, `queueid` int(11) NOT NULL AUTO_INCREMENT, `problem_id` int(3) NOT NULL, ...
0
votes
1answer
39 views

String templating technique

I am working on a fitness app that is going to deliver notifications to the user. I intend using MySQL events to populate the necessary tables, and then using an Ajax timer or Websockets or whatnot to ...
1
vote
1answer
47 views

Best way to handle column that doesn't conform to one particular type

I have a Settings table: CREATE TABLE `Settings` ( `Id` int(11) NOT NULL AUTO_INCREMENT, `Code` varchar(100) NOT NULL, `Name` varchar(250) NOT NULL, `Description` text NOT NULL, `Default` ...
1
vote
1answer
811 views

Can MySQL Workbench generate data?

Is there a way to generate mass rows of dummy data in a table for testing in workbench? If not, are there any free tools out there that is able to do that?
0
votes
1answer
776 views

Reset Variable when row value is changed

Below is an example of a SELECT statement. I have a variable @total that is set to 0, which works fine if I am doing a WHERE clause but I need the final total for each agent. Currently how this works ...
3
votes
2answers
3k views

Allow SELECT on specific column only

I have a User table with 3 column; name, email, password, etc. I would like to create another user that can only SELECT the name column. SELECT name FROM User; -- Ok! SELECT email FROM ...
5
votes
2answers
1k views

TokuDB optimize table does not reclaim disk space

Was running an optimize table command against one of my tables about 11Gig in size, surprisingly used disk space grew by 2Gig immediately after optimization process finished. I would expect the ...
-1
votes
1answer
139 views

how to count result set for select statment [closed]

I have to make query from DB. I found some solution but it isn't so precise as it need to be. Here result of my query: country weight Germany 1687.5 Gt.Britain 1687.5 Japan ...
0
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1answer
2k views

Get memory usage of mysql query during runtime

Is possible to obtain used memory in a running query? Something like: mysql> SELECT MEMORY_PEAK as memory; #return memory usage by mysql before run query mysql> SELECT id FROM table WHERE ...
5
votes
2answers
7k views

mysql multi threading for a single query

I have big db of size 8GB and having 9 million contacts in this db. When we try to retrieve all contacts, it takes nearly 1 or 2 hour (in some cases result in timeout) to retreive all contacts for the ...
3
votes
1answer
867 views

Replace MySQL table with data from csv

I have a CSV file on about 200 MB/1 mill rows, which is updated every night. I need the values from this file available in a MySQL table. I get this working by using LOAD DATA INFILE filepath REPLACE ...
1
vote
2answers
516 views

Indexing varchar column to search for first letter

I'm trying to optimize a legacy web-app where users can ask for a list of all records whose name starts with a given character. The query to optimize is: SELECT oggetto.id_oggetto, titolo, anno, ...
0
votes
1answer
105 views

Config settings in MySQL so that it saves data on disk monthwise/yearwise

I have billions of rows in my MySQL table. So when I do a select for a specific date range , it takes minutes to return results, or sometimes even hangs up. Is there any config settings in MySQL so ...
1
vote
2answers
159 views

Is column order reliable in UPDATE?

Can we reply on the order of columns in an UPDATE? SET @x = 0 UPDATE table1 SET col1=IF(col1 IS NULL, NULL, @x:=@x+col1), col2=IF(col2 IS NULL, NULL, @x:=@x+col2), col3=IF(col3 IS NULL, NULL, @x:=0) ...
0
votes
2answers
151 views

Grant access on a database to all users

I have a global database, as I all users should have access to it. Is it possible to grant permission on a database to all users? something like GRANT ALL ON my_database.* TO *@localhost; Even (for ...
7
votes
3answers
13k views

Making sense of INNODB buffer pool stats

After having read this page in the mysql documentation, I tried to make sense of our current InnoDB usage. Currently, we allocate 6GB of RAM for the buffer pool. Our database size is about the same. ...
1
vote
1answer
2k views

How to get MySQL to iterate a subquery in an aggregate select?

Because the vocabulary describing what I'd like to do can be so disparate, I haven't had any luck figuring out why MySQL 5.6 is doing what it does. Consider the following two simple queries: #1 ...
2
votes
1answer
3k views

Delete data from huge InnoDB table from MySQL Master and Slaves

We have some huge tables in MySQL database, We have already archived/deleted data older than 2012 in 2013, Now we need to archive/delete data older than 2013 means we need to archive data for year ...
5
votes
1answer
5k views

MySQL 5.6 on OS X 10.8.2 disconnects on user creation?

Via Homebrew I just upgraded from MySQL 5.5.29 to 5.6.10 and all my queries and existing users are working fine, but whenever I try to modify permissions or create users now MySQL disconnects me. Are ...
3
votes
3answers
2k views

MySQL query extremely slow after server restart

I am managing a very large database for a custom application I wrote to keep track of visitors. The DB server was rebooted for the first time in over a year - not even to install any updates, but ...
2
votes
1answer
102 views

MySQL : Till when MySQL retains binary logs?

I have multiple queries : Till when does MySQL retain the binary logs ? What is the default setting ? When does it start logging ? What does the number of the binary log file name suggest for ...
0
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0answers
30 views

MySQL: why provide size of a datatype in table definition? [duplicate]

Below is an example table definition: CREATE TABLE IF NOT EXISTS `mytable` ( `id` MEDIUMINT(5) NOT NULL AUTO_INCREMENT, `title` varchar(255) DEFAULT NULL DEFAULT '', `content` text ...
2
votes
1answer
3k views

How to use LOW_PRIORITY for heavy queries?

I have scheduled heavy UPDATE queries at administrator level, and since they are heavy UPDATEs with multiple JOINs, consume a huge amount of resources. I do not want them to stop end users from ...
1
vote
1answer
4k views

column auto updated after 24 hours in mysql

i have a table T1 with column : Name State time mon 1 2014-01-09 11:23:00 tue 0 2014-01-07 14:40:00 wed 2 2014-01-08 09:23:00 thu ...
0
votes
1answer
5k views

Declare variable mysql

I am new to mysql, I have been using SQL in the past. I am trying to insert rows into a table via creating a loop. But struggling with it. Any help? DECLARE @minid INT = (SELECT MIN(Product_ID) FROM ...
0
votes
1answer
51 views

Retrieve column info from next column

I have a query that is working but I figure I could enlist some help to make it more efficient. However before I show the query I would like to get a few answer on how others would do this. What the ...
1
vote
1answer
206 views

How to do two actions in conditional UPDATE?

In a query as SET @x = 1 UPDATE table1 SET col2 = IF(col1 = 'y', @x:=0, @x:=@x+1) Every time reaching the value of y in col1, I want to SET the @x:=@x+1 and after that reset the x to 0. In other ...
0
votes
1answer
1k views

My database keeps crashing on startup how can i repair it without it running?

I've got some problems with my database. I hope somebody can help me out. Problem: The database keeps crashing on startup. In my log i see a couple off these errors: [ERROR] /usr/libexec/mysqld: ...
3
votes
4answers
4k views

Update column with the sum of column in previous rows in MySQL

We have a table, essentially: id, amount, end balance, account_id I now want to re-calculate the end balance values (because of possible corruption) End balance is basically "end balance of ...
3
votes
2answers
6k views

Select every n-th row, don't pull the entire table

In light of the Meta discussion on allowing basic SQL questions on dba.SE I present an issue that I'm having now, for which the answer on Stack Overflow is inadequate and naive. I hope that there is a ...
0
votes
2answers
134 views

I can't get an import to go past 1.1gig

I can't get an import to go past 1.1gig. I have a large 4gig InnoDB table/database I would like to get on my "tried and true" box. Current config on this box I want to work with = Dell PowerEdge ...
0
votes
1answer
4k views

MySQL auto increment problem with deleting rows / archive table

A hosted server is running "maintenance" each weekend. I am not privy to the details. In a database on this server there is a MyISAM table. This table never holds more than 1000 rows and usually much ...
1
vote
0answers
146 views

MySQL SSL Master-Slave replication not syncing

I have originally posted this thread on stackoverflow and after a comment I moved it here. The original post can be found here. I have setup a typical Master-Slave replication scheme for my MySQL ...
-2
votes
1answer
202 views

Bulk Insert / Data Transformation [closed]

What techniques do people use to upload data from a flat file into a normalised database? We are planning on using MySQL or MariaDB. I have a number of large excel spreadsheets that I would like to ...
1
vote
1answer
110 views

Query result set

I've 1 query written in our legacy system. (using MySQL 5.5) Now, with growing data - the below mentioned query taking huge time. In our system, we've somewhat 2,000,000,000 (2 billion rows) approx ...
0
votes
1answer
2k views

Speeding up mysqldump / reload

Converting a large schema to file-per-table and I will be performing a mysqldump/reload with --all-databases. I have edited the my.cnf and changed "innod_flush_log_at_trx_commit=2" to speed up the ...
1
vote
1answer
91 views

Is an explicit KEY redundant if it is covered by a UNIQUE KEY?

I am auditing an application which I've been developing over the course of several weeks. I've noticed this in CREATE TABLE: UNIQUE KEY `baz_3` (`baz`,`foo`,`bar`), KEY `baz` (`baz`), Is the ...
0
votes
0answers
120 views

unexpected null returned from calculated columns

I'm working on a program that will calculate journey times based on bluetooth MAC addresses and i'm trying to nail down the mySQL commands I need before I get cracking on the software part of it. i ...
0
votes
2answers
70 views

Is it safe for me to switch from an 8GB server to a 4GB server? (Stats inside)

We are looking to cut some of our server costs and the only place I think it might be possible is our db server. We're currently running an 8GB rackspace cloud that houses a mysql instance and I ...
2
votes
1answer
2k views

How to call stored procedure inside trigger?

I have made stored procedure that will update product quantity as per product id. That works fine for me. Following is code : DELIMITER $$ CREATE DEFINER=`root`@`localhost` PROCEDURE ...
0
votes
2answers
382 views

Binary Log Format in MySQL

Reference manual for MySQL 5.6 states that " Some changes, however, still use the statement-based format. Examples include all DDL (data definition language) statements such as CREATE TABLE, ALTER ...
0
votes
1answer
165 views

multiple requests shut down mysql

I have some problems with my mysql database. I configured a server with the database and other services (apache, php) and put run multiple applications. There are two problems. Every day at the ...
1
vote
1answer
173 views

MySQL DB dynamic ranking or “static” separately saved

I have a table where I store the points with the connected categories and game-types of each user. There are different ways to get points. However everytime when the points need to get displayed in a ...
0
votes
0answers
9 views

Multiple requests shut down MySQL [duplicate]

I have some problems with my MySQL database. I configured a server with the database and other services (apache, php) and put run multiple applications. There are two problems: Every day at the ...
1
vote
1answer
709 views

MySQLdump on specific db date

I'm new in here and i don't really know where to start but here is my concern. I need to backyp a MySQL DB running under windows once a week. For e.g every friday i need to backup and transfer to ...
0
votes
0answers
63 views

Same table for real persons and fictional one

In my application stores both real and fictional persons (from movies, etc.) as well as stage names and alter egos. These entities have almost the same properties and are often referenced via foreign ...