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Mysql Execution Sequence


I need to retrieve the last value from a column in a mysql table, perform some actions on it, then add 1 to the original value and store a new entry.

I am worried that if multiple users access the database at the same time I will end up with duplicated 'new values'. Does mysql complete execution of a script before it allows access to another user or do I need to 'lock' the table in some way while the script executes?




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Related Forum Messages:
How To Create A Sequence In MySQL
I am not able to create a sequence in MYSQL 5.0
Want help on creating the same.

Basically, what I am looking for is, that I should get a number greater that the last one on every call to this sequence.

In Oracle, one can simply write something like:-
CREATE SEQUENCE seq_ordermaster
increment by 1 start with 1
maxvalue 999999minvalue 1
nocache
Nocycle;
And while calling, one can use it by selecting seq_ordermaster.nextval from DUAL

Considering the fact that there is no DUAL table in MySQL, how can One write such a sequence and also, how one can get the next value on each select statement?

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MySQL Variables, Modifying Microsoft SQL Sequence Insert For Use In Mysql
I have the following microsoft SQL statement that inserts 25 new
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I cant seem to get the variable decleration right. I tried using
DECLARE CurVal int but that generates a mysql error. How can I modify
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Mysql WHERE Condition Execution
I have 2 columns and I search rows with two conditions.

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How can I make mysql search columns with A condition first and after
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I would like to know, how mysql search works.
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Index On Long Column And Auto Sequence In Mysql
How do we create index on long columns in Mysql? we want to store the timestamp component of the data field in a long data type and be able to index on it.

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Mysql Shuts Down During Rapid Execution Of Querys
I am using version 4.0.12-nt of MySQL and when I hit the enter key
rapidly I can't connect to the database. The result is a message is
returned to me from mysql that says I can't connect because the
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page that my queries are on(their are four queries on this particular
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We have noticed that this only happens when we:

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Measure Execution Time Of Mysql Script
I am trying to measure the total execution time of a mysql script that I run using the mysql command line client in batch mode (-e "source myscript"). The --tee option does not work for the batch mode so that I could then gather and add up the execution times of the SQL queries as logged by the server.

Adding a tee command in the script itself is not working. Using the time command (in Linux , and timex is not available) on the mysql program is also not helpful as I think it does not include the execution time of the queries on the mysql server side, but only the system and user times corresponding to the client process.

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Can't Connect To MySQL Server On 'localhost' (10061) On Script Execution
Whenever I run this script:

<?php
$mysqli = mysqli_connect("localhost", "root", "rootnow");

if (mysqli_connect_errno()) {
printf("Connect failed: %s
", mysqli_connect_error());
exit();
} else {
printf("Host information: %s
", mysqli_get_host_info($mysqli));
mysqli_close($mysqli);
}
?>


I get this error message:
Connect failed: Can't connect to MySQL server on 'localhost' (10061)

I'm running Apache 2.0.58 with PHP 5.1.4 and MySQL 5.0.20 on Windows XP Home Edition.

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Maximum Execution Time Of 300 Seconds Exceeded (was "MYSQL Error")
I have a huge database 400mb+ in size which i have exported into a .sql file. I tried to run this export script into a new database and it runs fine until three quarters into the scripts execution and the following error appears:

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '<br / >
<b>Fatal error</b>: Maximum execution time of 300 seconds exceeded in <b' at li ne 1
I believe this error may relate to "delayed_insert_timeout = 300". How do I increase this limit in mysql - maybe it may solve the problem but then again it may not .

Any advice is most gratefully appreciated - As you can imagine if the script runs fine for 3/4 of it and then an error appears, stating the error is on line 1, it will take me days to go through the whole script (hundreds of thousands of rows) to find the error as I assume the error does not reside on line 1 as this line would have been executed.

I am running the script on mysql 5, and via source /path/****.sql on linux.

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What Is Execution Time Of A Query Based On? (was "a Mysql Question")
when selecting data from the database, does the time taken to retrieve it vary from 56k connections to T3 connections? or does it all depends ont he general server speed/amount of connections on the db?

im not sure if ive explained that in the best way for people to understand
but im sure someone will get what i mean

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Disrupted Sequence
Another brainteaser:

CREATE TABLE IF NOT EXISTS `test` (
`id` INT(11) unsigned NOT NULL auto_increment,
`cid` VARCHAR(10) NOT NULL,
`item` VARCHAR(10) NOT NULL,
`val` INT(11) NOT NULL,
`dt` datetime NOT NULL default '0000-00-00 00:00:00',
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1

In the above example table I need to find the first 5 highest values of val that break the sequential set of values. In other words: say I have values 49,48,45,44,43,40,39,37,36,34 of val in my table, with 49 being the highest value of val (need to sorted first, because values may randomly be dispersed in my table), then I want to get 47,46,42,41,38 as the query result.

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Create A Sequence?
I am creating an application that will contain three tables that need to share the same sequence. Upon digging through the docs, I do not see how I could do this.

Could someone give me some guidance into this?

Also, As I read the docs, when I am creating tables, there is something about an InnoDB? Sorry to be confused, but I am not sure how to begin creating my database, nor tables without this knowledge.

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Sequence Substitute
I have a problem about create sequence number which can be reset after MAXVALUE has been assigned. In the older version of mysql i can use "create sequence", but in the recent version i can't do that anymore. All i know in mysql ver 5 is "Auto_increment" which cannot be reset number without delete or truncate table.

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CREATE SEQUENCE ?
Tracing some examples in a book from Apress,
for some reason they go for Oracle in this book -
not my cup of tea, especially not when I am sitting on
a vista-terminal. Enough of my complaing.

How do I create a sequence in mysql ?

This is the example I am stuck with:

CREATE SEQUENCE SEQ_ID_GEN INCREMENT BY 1 START WITH 100 MINVALUE 1 CACHE 50 ;

How do I write that sentence in mysql ?

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Sequence Creation
I am not able to create a sequence in MySql.. But its giving error.

Can any one pls tell me how can i do that?

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Sequence Generation
I was wondering if there was something close to CREATE SEQUENCE in MaxDB for standard MySQL.

I'm thinking of just doing a table/stored procedure and calling it a day, but was wondering if MySQL had some other alternative.

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What Collation Sequence?
I've just transferred a small PHP/MySQL application from a Firepages phpdev5 install to an XAMPP install, so I've got new versions of everything. I used phpMyAdmin to export and import the tables of the database. When recreating the database on my new install I selected the default collation (latin1_general_ci) but my application is now displaying ? in place of a number of characters so I guess I got it wrong. I can't see where in the old phpMyAdmin (2.3.0-rc3) to determine what collation the database uses.

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Identity, Sequence, Serial
Does MySQL offer capability for any of the following?
- IDENTITY
- SEQUENCE
- SERIAL
Or is AUTO_INCREMENT the catch-all for the functionality of all of the above? I ask because I'm looking into Java EJB3 which describes support for any of the above (as well as AUTO_INCREMENT, so I'm not out of luck completely).

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Re-arrange Primary Key Sequence
i am facing a problem with my application when someone deletes a record and hence its key disappears breaking the sequence e.g

1 - entry
2 - entry
(3 - deleted no mere here)
4 - entry
5 - entry


When key is not there my AJAX application fails to run properly due to not finding next id. Is there any method to re-arrange primary key values to a proper sequence when one or more numbers are missing?so that i will write a query and whenever user deletes an item i will re-arrange the primary key sequence automatically

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Selcting Date Sequence
I am trying to return a set or rows that represent all of the days between two dates. For example, I want to select all the days between December 25th, 2005 and January 5th of 2006, and i am looking for it to return (shown here in CSV)
2005,12,25
2005,12,26
2005,12,27
2005,12,28
2005,12,29
2005,12,30
2005,12,31
2006,01,01
2006,01,02
2006,01,03
2006,01,04
2006,01,05

So, for any date, i want to select all the days in between. Any ideas?

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Order By An (out Of Sequence) Set Of Numbers
I'm having a problem as follows:

here is a an example table (tbl_test):

id | value
----------------
1 | hello
2 | hi
1 | bye
4 | cya
where the value field is variable.

and i want to select them so they are listed as follows:

id | value
----------------
2 | hi
1 | bye
1 | hello
4 | cya

is it possible to order by and array - something like:
SELECT * FROM tbl_test WHERE 1 ORDER BY id (2,1,4)

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Find The Number Of A Row In A Sequence
MySQL Code:
SELECT * FROM comments WHERE id=12345 ORDER BY rating

Is there a way to determine the position that this rows appears in the sequence?

Eg, so I can print out:

"This site is rated position x out of y"

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Bulk Insert Of New Records In Sequence
I am looking to create a querty that searches for the max value a field
called listnum in a table called tbl_listing and then interests 25 new
records with listnum's starting 1 higher then the max value.

ie if the highest listnum is 1000 it should insert new records with a
listnum of 1001-1024. All the other fields in the table can be blank.

Is there a simple (or not so simple) query that I can run to do this?

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How To Generate Sequence Values During Query
I have query like below:

SELECT part_no,part_nm,qty FROM tb_stok_out ORDER BY part_no

as result:

part_no part_nm qty

aaa asdfd 3
abab sdfsdf 4
abab adfdf 5

Is it possible in mysql to generate sequence number using query, so the result will be like below :

1 aaa asdfd 3
2 abab sdfsdf 4
3 abab adfdf 5
... etc

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Change The Sequence Of Column In Table
I am using MySql Query Browser I want to change the Sequence of Column in data table
e.g.

Before : table sequence is (UserID, Name, BOD)
After : table sequence is (User ID, BOD, Name)

How can I do that?

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Create Sequence Syntex Errors Out
I installed mysql 5 and trying to setup database. Somehow it can't create sequence. it throws generic 'check the manual that corresponds to your mysql server version......'.

I have tried just about anything nothing works.
Also tried to reinstall mysql few times--same thing.
Also tried to go through mysql 5 manual nothing is in there for sequence.
Or sequence is not supported with mysql version i have?

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Inserting New Data Within A Structured Sequence
I'm trying to organize rows in a specific sequence. However, I also want the capability to insert new rows within that sequence and not simply append them to the end of the dataset as autosequencing would have you do. How is this accomplished?

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Extract Data According To Preset Sequence... How?
wondering whether i can make this work...

first, i will make an array like this:

Quote:

$category_id[]="10,6,9,8,3";

then i wanna extract the information( category name, category id, and sub category into array and arrange them in the preset sequence in category_id[] above.

Quote:

$query="select * from category order by $category_id[] ";
$result="mysql_query($query) or die(mysql_error());

while ($row=mysql_fetch_assoc($result))
{
echo $row['category_id'];
echo $row['category_name'];
echo $row['subcategory'];
}

the output i wish to get is like this:

Quote:

1st result:
category id: 10
category name= the name of category 10
sub category=
sub 1 category 10
sub 2 category 10
sub 3 category 10

2nd result:
category id: 6
category name= the name of category 6
sub category=
sub 1 category 6
sub 2 category 6
sub 3 category 6

3rd result:
category id: 9
category name= the name of category 9
sub category=
sub 1 category 9
sub 2 category 9
sub 3 category 9

I'm confuse in the extraction info according to the preset sequence... can anyone please share some ideas? will this idea works?

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Ending Of Execution
is it important to free resources and end connection after every code execution...
i found a few codes examples and they don't usually end with DIE or EXIT... so i'm curious if thats a security risk?

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Execution Performance
Just out of curiosity, does adding LIMIT 1 to the end of single row UPDATE queries improve execution speed at all?

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Execution Time
After we execute a statement in mysql, it reports the query execution time in the format: n rows in set (t sec).

We may do something like this to get the execution time:
$time_start = getmicrotime();
mysql_query( "" );
$time_end = getmicrotime();
$time = $time_end - $time_start;

But it includes extra CPU time to run two getmicrotime() functions and one subtraction.

Is there any way to obtain the execution time directly from mysql without running extra functions or calculations?

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Log Execution Queries
I am writing a program in python, and I use mySql v1.2.12, I wanna know If mysql logs any command such as wxecution commands(like INSERT, UPDATE, DELETE), if yes how can i access them?
thanks all

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Automation Of SQL Execution
I am looking for a tool or process to queue up many sql requests and automatically execute and deliver back via email - to enable around the clock processing.

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Asynchronous Execution
I have the following situation

php file 1: an SQL writes data to the database
php file 2: an SQL reads data from the database

Some users report errors that MIGHT be due to the SQL in file 1 not being executed, before they click on a link to open file 2. So they get out of date information.

I want to know if this is technically possible, whether this might indeed be the problem, that if a database is very busy, that SQL statements are queued and data retrieval may read obsolete out of date information, because the data storage SQL has not been executed yet.

And if this is the problem, I would like to wait in file 1 until the data has actually been written.

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Max Sequence Number In Claim Transaction Table
have a table that contains a transactional history showing how a claim amount has changed over time. Each time the claim amount is updated, a new claim sequence number is used.

The fields I have are Claim Number(CLMKYT), Claim Sequence(CLMSQT), Claim Amount(£)(OUTSTT) and Date the claim was entered/updated (EFFDTT)

I want to pull out the latest (most recent) claim amount for each claim as at any particular date.

I have the below query which I think almost gets me there, but not quite!

Code: .....

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Generated Sequence # Based Upon Content Of Row Being Inserted
I have a table -

CREATE TABLE `sample` (
`Id` smallint(6) NOT NULL auto_increment,
`division` varchar(5) NOT NULL,
`secion` varchar(5) NOT NULL,
`div_sect_seq` smallint(6) NOT NULL default '1',
PRIMARY KEY (`Id`)
);

I'd like to write the insert statement that would generate the next div_sect_seq number based upon the value being inserted into the table.

Let's say that the table contains:

|--id--|-division-|-section-|-div_sect_seq-|
| 1 | SC | XX | 000001 |
| 2 | SC | YY | 000001 |
| 3 | SC | XX | 000002 |

I'd like to insert a row for divsion = 'SC' and section = 'XX' with the next div_sect_seq (which would be the max value of div_sec_seq + 1 on the sample table for the division and section) which should be the value of 000003.

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Primary Key Field: Varchar(32) Versus Sequence
I got in the habit of coding primary key fields as varchar(32) that was generated by an md5() since it was a public site and I wanted to avoid people guessing record numbers (for other reasons).

Is there a performance problem with doing that?

If so, how do you tackle the same concern?

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Ordering By Sequence Field With Empty Values
I have a sequence field in my db table that I'm using to order a list. I'm trying to ORDER BY this field, but it puts the empty values before 1 such as
empty, empty, 1, 2, 3, 4
instead of
1, 2, 3, 4, empty, empty, empty
How can I fix this?



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Query Execution Time
I m using inner join where there is no keys (Primary and foreign). I want to know that Does key affects execution times?

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How To Get Time Execution Of A Query?
Do you know how to get the time that a query executes? Is there a formula on how to get it?

Example:

Note: I have 5000 data in the table cars

$result = mysql_query("Select * from cars");

Question: How to get time of executing the query above?

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Improve The Execution Time
i am new to db2 want to ask questions about the performance of my sql commands for a view based another 3 views

the sql commnads are as following:

create view b_central_subgroup as
select communicator as central_member, project_id as project_id
from b_normalized_communicator
intersect
select initiator as central_member, project_id as project_id
from b_normalized_initiator
intersect
select monospeaker as central_member, project_id as project_id
from b_normalized_monospeaker

it takes 4.4 seconds to execute this sql.

it likes that the time is the summ of the other three views.

Can the execution time be reduced through some other methods?
If it is possible , then how ?

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How To Get Query Execution Time
How to get query execution time in "mysqlquery.log" files

I am using:

Linux 7.3
mysql 4.1

How to display the query execution time for each and every query in log files.
i have configured "slow-log-query" and "mysqlquery.log" in "my.cnf" is pasted below.

log = /var/lib/mysql/mysqlquery.log
log-slow-queries = /var/lib/mysql/slowquery.log
long-query-time = 0
slow-launch-time = 1

then i can get a output in "mysqlquery.log" like,

070830 9:24:29 2 Connect root@localhost on
2 Init DB jbdatabase
2 Query select count(*) from vacancy1_table
2 Query select category,listcategory from category_t
able order by category
2 Quit


but i need to display the "timetaken of each end every executed query" along with the query in the above logfile like,

E.g:select category,listcategory from category_table order by category(0.03 secs).

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Query Execution Status
How can we know that , the last executed query status like executed successfully or not.

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Query Execution Too Slow!
I have migrated from MySQL 4.1.22 to MySQL 5.0.45. Many of the queries that were working on my old server is working too slow in my new server(MySQL version 5.0.45).

I am not aware why is this happening. Actually there is no error message or query failing. The query is executing, but the time taking to execute the query is too long. This problem is not occurring for all queirs, but only for some complex queires, that is queries with Left Join or Right Join, Group By etc.

I have also checked the MySQL details through SSH(that is by mysql> SHOW VARIABLES;)

Now one thing I found is there is lot of difference in key_buffer_size, table_cache, join_buffer_size, read_buffer_size, read_rnd_buffer_size , table_cache etc between my new server MySQL and old server MySQL.

Will this be the reason for query execution taking too much time.

Can any one guide me why this is happening. The striking thing is that these quires was working very much fine and faster in my old server.

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How To Get A Query Execution Time?
How to get a query execution time?

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Measure Execution Time
I would like to measure the execution time of my queries in order to evalutate the performance in/decrease for different changes. Even if I use 'sql_no_cache' the query executes MUCH faster the second time I run it, and is therefore not representative of the true performance. How to I avoid this problem?

I'm using MySQL 4.1 on a windows server 2000. I be glad to get an explanation to why the query executes faster the 2nd time.

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Last Query Execution Time
Is there a way to retreive the elapsed time for the prevously executed query?

Alternatively, Is there a way to query the current time in fractions of a second?

I am attempting to use a stored procedure to execute and track the time it takes to run some queries and other commands.

The logic of the stored proc would go something like this.....

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Query Log With Execution Time?
I have developed a big property portal web site and have probably written about 1000 different SQL queries in the process (OK, maybe only 500 or so) but a lot.

The site is now gaining popularity and although it is on a dedicated server I want to make sure that everything is running smoothly. I have optimised several tables with indexes etc. and have sped up certain tasks, but would like to know if there are any other queries that take too long and should be optimised.

Is there a way to log all queries together with the time it took to execute the query? Is this already logged and if so - where is it?

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