MYSQL :: How To Avoid Previous Results

How To Use Previous Select Query Results In New Select Query?
I have tested everything and it works OK in its current form. However, what I need help with is the part of the query highlighted in red.

As it currently stands, the PHP while statement loops through the rows and echos out the html. The issue I have is that it echos out the same speaker name and subject type for each iteration. Now I know this is happening because I have set subject.event_id = 1, so what I need is to use the event_id of the current iteration as the clause and that is what I need help with....

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Avoid Adding More Than Once
im trying to do what i think is a fairly easy query but im having some problems.

basically i want to only include a certain row of data in the results if it has previously met a certain criteria. however if it has met the criteria more than once i still only want it to return once.

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Avoid Self-joins
I have a table that has values of variables for certain entities. The
columns of interest are targetID, variableID, and valueID. A row (1, 5,
9) means that target number 1 has a value of 9 for variable 5. Being
denormalized, target number one will have many possible rows in this
table, one for each variable for which it has a value.

My problem occurs when I want to find out what targets match a certain
set of variable values. For instance, I want to find out what targets
have a value of 9 for variable 5 and a value of 25 for variable 10. I'm
thinking that this can be a simple self-join:

SELECT mya.targetID from mytable as mya
LEFT JOIN mytable as myb
ON mya.targetID=myb.targetID
WHERE (mya.variableID=5 AND mya.valueID=9)
AND (myb.variableID=10 AND myb.valueID=25)

Does this make sense so far? The problem is that this doesn't scale.
When I have more than 31 variables and I need to evaluate them all,
MySQL breaks: I can't do more than 31 joins.

My design calls for perhaps 80-100 variables, so even 64-bit
architecture with a limit of 64 joins won't get me there. This is NOT
an architecture or platform issue - I need a design and a data
structure that will scale to lots of variables.

I need another data structure that won't get me stuck on too many
joins.

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Overhead Avoid
When you delete rows in a table, you often (always?) get overhead, but what is it exactly. How do avoid it.Can anybody give me a small good description.

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Avoid Repeat Typing
I am a newbie in MySQL. I would like to know how to avoid repeating
typing an SQL statement when an error occurs after execution. That is,
if an error occurs I should be able to retrieve the statement that I
had written and correct the mistake. It is agonizing to keep on
repeating a statement that can take five minutes to write just because
one mispelled a word or missed a comma.

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How To Avoid Repeat Typing
I would like to know how to avoid repeating
typing an SQL statement when an error occurs after execution. That is,
if an error occurs I should be able to retrieve the statement that I
had written and correct the mistake. It is agonizing to keep on
repeating a statement that can take five minutes to write just because
one mispelled a word or missed a comma. I use windows 98.

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Avoid Duplicate Entry
I have a table with 10 columns and i insert data into it which is unique in a column called (scrape), so to do that i use
Code:

<?
$reb = select count(*) from table where scrape = '$scrape';
if (mysql_result($reb,0) > 0) {
echo "Item Already Added!<br>";
} else {
add the item
}
?>

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How To Avoid Duplicate Records
I need to filter out duplicates for every 30 seconds. say i have two duplicate records within the 30 seconds limit. I need to show up only one. If there are identical records but with a different time settings(say above 30 seconds) then i need to display it. I need to restrict duplicate records within 30 seconds.

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How To Avoid NOT EXISTS In MySQL 4.0.26
I tried to use NOT EXISTS but recently found out that it is supported since 4.1. Now I'm trying to avoid it but I can't figure out how to do this. The Problem is that I have a table with (among outhers) a column SessionId and action.

Action may be opened and closed. Now I want to get all those sessions which are in state open, i.e. which have no line with action = closed. My first attempt was:

select sessionId
from audit AS a
where action = 'opened' AND
NOT EXISTS (SELECT * FROM audit AS b WHERE b.sessionId = a.sessionId AND b.action = 'closed')

Could anybody give me a hint how to get an equivalient query without a subquery?

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Avoid Looping In Queries
I have a table structure as shown below

slno | filename | parent | type
0 | Button | awt | file
1 | awt | java | folder

I am making 2 database calls till I get to parent=java. Below is a very simple query that I am using

select parent FROM api where filename=Button

The above query would return me "awt" since awt is not equal to java, I am looping to make another query by taking the value

select parent FROM api where filename=awt

This query would return me "java" and the condition is satisfied.I wanted to avoid doing that and get that in a single statement.

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Optimization :: Avoid Order By
I need to get the last entry of a table, so I'm using the following query:

SELECT * FROM table WHERE (some conditions) ORDER BY date DESC LIMIT 0,1

Does anybody know an another way to do that? Can I keep a ordered table and than avoi the use of "order by"? If yes, how can I do that?

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Avoid Couples In The Resultset
I use a query like this:
select t1.id_topics, i1.id_indices , t2.id_topics from indices i1, indices i2, topics t1, topics t2
where (i1.ind ='test' and i1.id_urls=t1.id_urls and i2.id_urls=t2.id_urls and i1.ind=i2.ind and t1.id_topics<>t2.id_topics)

it gives results like those:
"id_topic1","id_indices","id_topic2"
36,682,34
37,682,36
36,682,37
37,682,34

I would like to eliminate the "inverted" mates of couples in the resultset. That means in the example
"36,682,37" should be eliminated since "37,682,36" is already part of the resultset. Is it possoble to express this request in the query?

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Command Used In Avoid Retyping
I don't want to retype a command once I wrote it. Does anyone knowa about an option that would just that like in a dos shell where you can use arrows to get back any command you have entered.

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Count(*) To Avoid Duplicates
This is for (2) seperate sites that share the same login table (same username/passwords will access both sites).

Users may register at either site, if they choose, then they should login at the other site to "complete" the last phase of registration at the other site to insert remaining needed values.

Problem is with duplicates. When some users won't login, as they should, "complete" the process at the other site. They may bypass and register anew like anyone else at the site for the first time. (Even though there is a pre-registration page at both sites -- asking if users have already registered at the other site prior to arriving at the second -- directing a login to complete the process.)

Reason this is a concern is that one site has a (6) page registration process, inserting to (8) tables.

My idea (aside from aleady checking for unique inserts on usernames/passwords/emails) is to check on the complete phone number.
To be used on a conditional show region on the second page of registration -- if the latest registrant entered the same phone number asmay aleady exist in the table, (previously enterered while registering on the other site and forgot about it) -- this 2nd registration page will not show due to the: count(*)

Starting with 'Area' code, is this practical/how to combine all three?
Anyone have better suggestions or experience on handling two site duiplicates?

Would there be any benefit in having ALL USERS (both new and prior from the "other" site) fill out the the 1st registration form (on the (6) page registration site) where they are then directed to login to complete the process?

'AREA' 'PRE' 'PHONE'

SELECT *
FROM `Members`
WHERE `Area`
IN (
SELECT `Area`
FROM 'Members`
GROUP BY `Area`
HAVING count(*)>1
)

note: some registrants have same company names fir satellite/regional offices

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How To Avoid Race Condition?
How do I lock a table for one of my insert (followed by a read) queries on a table such that other simultaneous insert/read queries on that table are put off until the first one is complete? I am trying to avoid a potential race condition.

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Avoid Zero In Interger Datatype
Is there any way to avoid zeros which automatically entered in database in those column those have integer data type.

or i want to enter - instead of those zero

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How To Avoid Using Inefficient IN/NOT IN In A Query SQL Statement
The inefficiency of the IN clause in SQL statement is well known. Could anyone suggest some workarounds for the following case.

I have three tables tb1,tb2 and tb3. I would like to sum up field values from two tables,and show a list of person name whose name appear in tb3. How to do this using a SQL statement.

Code:

tb1
Name Salary
Bob 1000
Tom 2000
John 3000
Winson 4000

Code:

tb2
Name Bonus
Bob 100
Tom 200

Code:

tb3
Name
Bob
Tom

I would like to get the following result

Code:

Name Total
Bob 1100
Tom 2200

i would like to use the following statement

Code:

SELECT
tb1.name, (tb1.salary+tb2.bonus) as remuneration
FROM
tb1
LEFT JOIN
tb2 on tb2.Name=tb1.Name
WHERE tb1.name IN tb3

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Trimming Leading Zeros- How To Avoid?
i've been working on a database project and have run into some undesirable behavior. i have a field called time of type varchar(10), and i'd like to insert a value '0004587716' into this field, but the result of the insert is '4587716'. it looks like the default behavior is to trim the leading zeroes.

is there any way for the original value to be inserted with the zeroes? maybe some other data type?

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How To Avoid Double Counting In One Query?
Now I`m doing COUNT(*) in SELECT clause and WHERE clause. How can I rewrite this query to do it only once?

Here is my code: ....

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Trying To Avoid Using Query Inside While Loop
I've done a lot of reading on here and I learned from some of Rudy's posts that it's a bad idea to do a query inside a while loop. I don't know why this is but he seems like an expert so I'll listen

What I am trying to do is take the top ten points from a player and display them. First I will post the tables then the code.

CREATE TABLE `tournament` (
`gameid` int(11) unsigned NOT NULL auto_increment,
`gametype` tinyint(2) unsigned NOT NULL default Ɔ',
`gamedate` datetime NOT NULL default &#55612;&#57200;-00-00 00:00:00',
`leagueid` int(11) unsigned NOT NULL default Ɔ',
`seasonid` int(11) unsigned NOT NULL default Ɔ',
`roomid` int(11) NOT NULL default Ɔ',
`gamename` varchar(50) NOT NULL default '',
`cost` mediumint(4) NOT NULL default Ɔ',
`seats` mediumint(4) NOT NULL default Ɔ',
`notes` tinytext NOT NULL,
PRIMARY KEY (`gameid`)
) ;

CREATE TABLE `tournament_results` (
`id` bigint(20) unsigned NOT NULL auto_increment,
`gameid` int(11) unsigned NOT NULL default Ɔ',
`memberid` int(11) NOT NULL default Ɔ',
`place` smallint(4) NOT NULL default Ɔ',
`earnings` smallint(5) default Ɔ',
`bounties` float unsigned default Ɔ',
`points` float NOT NULL,
PRIMARY KEY (`id`)
);
Now the follow code would be what I would use if I just wanted to add all the points and not limit it

PHP

mysql_query("SELECT
members.firstname,
members.lastname,
SUM(tournament_results.points) AS tpoints,
COUNT(*)as numgames,
AVG(tournament_results.points) AS apoints,
members.memberid AS membersid
FROM
members,
tournament_results,
leaguemembers, tournament
WHERE members.memberid = tournament_results.memberid
AND leaguemembers.memberid = members.memberid
AND leaguemembers.leagueid = '$lid'
AND tournament_results.gameid = tournament.gameid
AND tournament.seasonid = '$sid'
GROUP BY members.memberid
ORDER BY tpoints DESC");

That will total all of their games but I want to limit it their top 10 scores how can I do this without introducing a query inside of the while loop?

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Avoid Duplicate Records In Within 30 Seconds
I'm working with php. I have a auction site, more or less. I want to create all-time rankings. The idea is to display where a seller ranks (all time) in the number of sales.

So for example, I'd display
John Doe All Time Sales Ranking: #138

I'm not exactly sure how to go about this.

$query = "SELECT count(*) as counter, SellerName FROM sales GROUP BY Sellername ORDER BY counter DESC";

This query would give me the data to list all of the Sellers in desc order by the number of sales.

In php, I could probably count until the Sellername was equal to $Sellername (already defined in their profile page), but I was hoping there would be a way to do this entirely in MySQL.

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Mysql Running All Queries Double ? How To Avoid ?
Sometimes, when my database server has been slow and building up hundreds of queries, I have the impression that mysql is running 'double' of triple . It's hard to explain, but when I look at mtop (a tool to see what queries are active and what time they take to finish) , I see a lot of queries that seem to hang and that are present more then once. Some of them have unique data in them that can not happen just by refreshing a form. When the peak moment is over, and I check my site, then I sometimes see for example the exact same forum post 3 or 4 times in the same thread. Needless to say, this causes a lot of extra load on my database.

I'm not sure what really happens, but it seems like mysql server is just piling up queries wich it can not process fast enough, and those queries seem to come in several times again. I use seperate webservers, but even if I reboot them all, the extra queries still come in as soon as the webserver is back up and php scripts start to work again. The only way to stop it all, is to restart mysql, but that is something that I can not just do very easily. I rely on several heap tables for my site and they need to be refilled with data from normal tables. So restarting mysql is something I only like to do at night, with very few visitors online.

I hope I'm explaining my problem well enough. And I hope there is a way for me to check what really is going on, and if there is a way to stop mysql from 'running double' ?

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Cleaning Up MySQL Connections To Avoid 1040
Well, I'm trying to run
PHP

$result = mysql_query("SHOW FULL PROCESSLIST");
while ($row=mysql_fetch_array($result)) {
    $process_id=$row["Id"];
    if ($row["Time"] > 200 ) {
        $sql="KILL $process_id";
        mysql_query($sql);
    }
}

To clean up my connections, as I'm getting a 1040 error "too many connections". Of course, I can't run this until I can actually connect, unless there is a way around somehow. I don't have any admin rights, I just have a web-based "php my-admin" module to run the db.

Every page people access opens a mysql connection, and then it is closed with
PHP

mysql_close($connection);

. Would putting in
PHP

<?php mysql_close($connection); $NASI_connection = null;?>

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Scheduling Replication To Avoid Bottle-neck Updates
We have a circular master-slave setup where any one of the 2 servers
can become master at any time (by human decision). The two servers are
placed at geographically different sites. The servers contain à number

of databases which are all replicated both ways.

When we have full usage of one master ~500 inserts/updates per second,
the bandwidth between our sites becomes a significant bottle-neck. This

we can accept at database level not on server level, ie
- if database A on site B has a lag of 30min because of important
activity on database A on site A, it is acceptable.
- if database B on site B has a lag of 30min because of important
activity on database A on site A, it is not acceptable.

Is there a work-around? We never have updates concerning 2 databases in
the same query.

Creating multiple mysql servers at each site could be one, but that
means some 10-50 servers on every physical computer. What side-effects
does that create?

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Would Like To Avoid Iterating Through Data And UPDATING Multiple Times
I've got product data that belongs to a category table. The business requirement is for the user to be allowed to update the order in which products appear in that category. There is a field called product.sequence for that very purpose.

I'm being given the product id's in order for each category.

Do I have to iterate through the data in PHP and UPDATE the table w/ many SQL statements, or is there one SQL statement where I can provide the list of products to update in order?

I've used MySQL user variables before (e.g. SELECT @m:=0;) but I don't see how I can use it here... Is what I want possible in one query?

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What Field Type To Use To Avoid Blank Spaces In Fields
Can you tell me the best field type to use here?

I've got a table in mysql with all 5 fields defined
as tinytext

Problem is when I export this to to a text file for notepad
each field is padded out by several blank spaces,
and i think my eamil program doesnt like this type of structue :
field1 , field2 , field3 , field4

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Subtract Previous Value.
I'm trying to get one column of numbers to subtract from another column and to keep a running total. Column A is a dollar amount from an invoice. Column B starts out with an opening amount ($10,000) and I want to have Column A to subtract from that.
Code:

COLUMN A--------COLUMN B
$0.00 $10,000
$1000 $9,000
$500 $8,500
$2000 $6,500

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ID Of Previous Insert
Im thinking i need a transaction here. I want to insert a record into a table, which has an autoincrement field as the primary id. Then use this id to insert into another table. In the time between the first insert and then getting the id, couldnt there possibly be another user that causes an insert and hence the id the first user gets back isnt correct ?transactions to the rescue ?

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Previous Record
I need to get a previous record from database - i need to retrieve records which differs from the previous one about 5s example:

select eventDate,previousEventDate,eventDate-previousEventDate as delta from events having delta<5 order by eventDate;

eventDate is normal column from table

previousEventDate is an "alias" for the previous date ... how can I write it in SQL?
Please help. I can use SELECT as subquery, but it would be probably really slow, the table will have 100000s maybe milions of records soon.

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Previous Row Comparison
I have a table in this format:

Column A | Column B
1 | 2
1 | 3
1 | 4
2 | 5
.....
.....

What I want to do is something like this:

If in Column A there is a change in the number i.e. from the above table there were many 1s which transitioned into a 2. I want to record this change. I want to extract these two rows into another table. How can I make this possible?

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Using Data From Previous Row
I only want to select the current row if a field in the previous row is not null.

Is it possible to write such a query?

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Previous To Last With A Certain WHERE Condition
How do i fetch the previous row record with the same WHERE when the last record has only a lately date.

for example

field CConsorcio CRubro ImporteA FechaA

1 105 1000 2006-05-10
2 110 30 2006-05-12
5 105 300 2006-05-13
4 104 600 2006-05-14
2 103 800 2006-05-15

the WHERE CConsorcio=2
the last record: 2,103,800,2006-05-15
and i want to select the row: 2,110,30,2006-05-12

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Get Next And Previous Records
Our website has a portfolio database which uses a column entitled 'list_order' to set the order of how we want the projects to display in a list. Each project has a link to click into it to see the full details of the project.

Inside this details page we would like to add a View Previous Project and View Next Project link which would allow the user to navigate through our projects. The problem is that we are using an order set by 'list_order' and not an auto incremented column.

How would I setup the Query to grab the previous and next rows no matter which project the user clicked on? For example, our database has these records:

id - list_order
102 - 100
89 - 200
7 - 250
30 - 300
97 - 400
20 - 500
62 - 600
88 - 650
103 - 700
85 - 800
112 - 900
95 - 1000

So, if someone clicked into id 97, we'd need a query that would grab id numbers 30 and 20 for the previous and next id to create the links.

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Select Previous And Next Id After Id=# ?

For a gallery I'm trying to query for a picture by its id and also get some images before and after that id (according to current sort) are there references like DOM previousNode or stuff like that to use in the WHERE statement? Or how could I do this?

Currently I have: ($picId is a php variable)

'(SELECT id, picUri, picUriSmall FROM pictures WHERE id < '.$picId.' ORDER BY id DESC LIMIT 2)
UNION (SELECT id, picUri, picUriSmall FROM pictures WHERE id = '.$picId.')
UNION (SELECT id, picUri, picUriSmall FROM pictures WHERE id > '.$picId.' LIMIT 2)'
This works but doesn't seem to be the best way. I want to be able to have it working for other sorts than by id. And the two first images gotten by this query will be in reversed order (can be fixed in php).

Is there a way to ask for my picIDs position in a query and then use another query to make the LIMIT 10,14 if my image was in position 12?

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Paging With Only Next/previous
I'm running PHP + MySQL (innodb) and in some pages, the paging is slowing down the system a lot.

Now I've seen on some sites that have paging implemented in an interesting way. They only let you go forwards and backwards one page at a time, and some don't even tell you how many results there are.

For instance if you look at google search results, they only says "about XXX results". Plus they never actually let you jump to the last page.

I'm thinking of implementing my system this way in certain pages as well, to cut down on the load times. However, I'm exactly sure how that cuts down the load. Can someone shed some light on this?

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Selecting Item From Previous Row
Is it possible to get an entry from a previous row in a select statement?

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Determine Previous Month
basically I need to display a list of "unpaid" statements for the previous Month, no matter what day the search/request is made on. I know MySQL has the DATE_SUB function where I can subtract 1 Month from the current date, but will that subtract the date exactly 1 month to the day ? Or will it simply give me the Month as I need ?
What happens if the search takes place on the 31st of a month (for example: July), yet the previous month only has 30 days (June). Will it roll back to the previous month correctly or think that the date is 31st June or try to roll back further until it finds another month which has 31 days ?

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Previous, Current, And Next In One Query?
This situation has come up a couple times and I've wanted to know if there's a better way to do it.

Given something unique (an ID number, a specific date/time, etc) I want to find the thing that comes before it and the one after it when sorted by something else. Oh, and the "something unique" isn't sequential - random intervals between each.

Code: ....

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Getting Next, Previous Record After INSERT
When I insert a record in a given index order I want to be able to traverse to the previous or next record of that index order, before or after the one I inserted. So for example if I insert a record with an address of "20 Heather Court" using an address index order, I want to be able to push a Next button (on a Web HTML form) to go to the record corresponding to "21 Heather Court" or, if I press the Previous button I
I want to be able to go the record corresponding to "19 Heather Court". Assuming of course that both the Next and Previous records exist before I insert "20 Heather Court".

If I change the index order to customer first name and insert a new record for a customer named "Harry" I then want to be able to push the Next button and see the record for a customer named "Jan" or if I push the Previous button I likewise want to pull up the record for a customer
named "Garry". Assuming that the records for Jan and Garry already existed before I inserted the one for Harry and that they became the Next and Previous records with respect to Harry's after the insertion.

Using an auto increment field does no good because every time I change the index order any kind of sequential relationship between the values in the auto increment field gets totally messed up.

I have also tried statements like " SELECT * FROM Customers WHERE Customer_ID <349 ORDER BY `Customer_ID` ASC LIMIT 0 , 1" without success if there are 10 records before the one with a Customer_ID of 349. A LIMIT of 0,1 will start at record 0 for only 1 record. I want to pull up the record immediately preceding the one with a Customer ID of 349.

In short is there some way to tell which record is Next or Previous to one that I insert under a given index order?

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Get Previous And Next ID Of Current Record
I want do create a "Previous" and a "Next" link, all I have is the ID of the current record. Is there a good way to get the previous and next id of a record with a single SQL Query?

example:

ID's: 4,10,7,9,13

I open my page and show all details from the record with the ID 7, now I want to create the links and I need the previous and the next ID, 10 and 9.

I could make a query that returns only the ID's and loop through the recordset till i have my ID's but that's such an ugly solution, not to mention the performance issues.

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Phase Previous And Next Record
I want do create a "Previous" and a "Next" link, all I have is the ID of the current record. Is there a good way to get the previous and next id of a record with a single SQL Query? example:

ID's: 4,10,7,9,13

I open my page and show all details from the record with the ID 7, now I want to create the links and I need the previous and the next ID, 10 and 9.

I could make a query that returns only the ID's and loop through the recordset till i have my ID's but that's such an ugly solution, not to mention the performance issues.

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To Find The Previous Record
I am preparing a ledger using PHP and mysql....I just want to bring the previous closing stock value as the opening stock value of the current transaction.For that i need to find the closing stock value of previous transaction....Is it possible to write a query to find the previous record?

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Show Empty Field On Same Previous Value
I have this query now:

SELECT table_2.id,
table_1.naam,
table_2.bedrag
FROM table_2
LEFT JOIN table_1 ON table_2.table_1_id = table_1.id

this is the result:

id naam bedrag
1 pat 200
2 carl 100
3 carl 300
4 bob 500
5 bob 750
6 bob 800

what I want is get the double names replaced by a empty or space:

1 pat 200
2 carl 100
3 300
4 bob 500
5 750
6 800

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How To Avoid Previous Results

I want to omit all results(id) from the first query in 2nd query , without using sub query...