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Parentheses: Query Works With 4.1.7, But Not With 4.1.11


Since we updated to the newest MySQL version (Windows) some of our queries do not work any more.

It's reproducable by this (dummy) query:

SELECT B.ID from ((SELECT * from A) AS T1
INNER JOIN B a ON B.ID = T1.ID);

This works with 4.1.7, but not with 4.1.11, unless the parentheses are removed:

SELECT B.ID from (SELECT * from A) AS T1
INNER JOIN B a ON B.ID = T1.ID;

Does anybody know why MySQL changed its behaviour that way?

I know the parentheses in the first query are not necessary, but it would be quite difficult to search through all our queries for unnecessary parentheses.




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Query Help. This Works, But I Don't Think It Is Good Practice
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comments:
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comicid
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how much significant increase would it gain on performance, do we really need care this ?


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PHP
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Well, I am using an UNION, and while both of the queries works fine while used individually, they don't work while in the UNION.

Here is the code -

PHP

(
SELECT *
FROM job
WHERE date_fin !=0000-00-00
ORDER BY date_fin ASC
)
UNION (
SELECT *
FROM job
WHERE date_fin =0000-00-00
ORDER BY date_creation ASC
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What do u think guys?

Note : MySQL version 4.1.21

Note : Not working means, this part is not working => 'ORDER BY date_fin ASC', means, the returned results are not ordered as I want.

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UNION
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I am new to MYSQL and am trying to understand how to make queries... I am moving from Microsoft Access where it is GUI driven and easy!

I can make a simple single query using MYSQL Query Browser, say:

qry1: SELECT ID, Area FROM data GROUP BY Area

How can I store this as a query inside MYSQL, rather than having to code it each time?

In Microsoft Access I could enter a variable ($VARIABLE) and then pass by code to the query:

qry2: SELECT ID, $VARIABLE FROM data GROUP BY $VARIABLE

How can I store this as a query and then pass the variable from code?

In Microsoft Access I could base a query on the results of another query, so following example above:

qry3: SELECT qry1.Area, data.ID FROM qry1 INNER JOIN data ON qry1.Area = data.Area;

How can I store this as a query in MYSQL.

How To Create Efficient MySQL Query From A Pseudo Query
I'm trying to build a webapplication where users can search for a person having a particular preference for color and material. To store this information I use the following structure (a MySQL dump can be found at the end of this post):
*table person with fields:
-persid: autoincrement id
-name: name of the person
*table material with fields:
-materialid: autoincrement id
-material: name of the material eg "wood"
*table color with fields:
-colorid: autoincrement id
-color: name of the color eg "green"
*table persmaterial with fields:
-persmatid: autoincrement id
-persid: link to table person
-materialid: link to table material
*table perscolor with fields:
-perscolorid: autoincrement id
-persid: link to table person
-colorid: link to table color

In the webapplication the search can be entered by the users as a kind of pseudo query:
(color=red OR color=blue) AND color=green AND material=iron

My question is: how can I automatically transform this pseudo query into an efficient MySQL query?
I have tried out some different options:


Option 1:
(SELECT p.persid FROM person p, perscolor pc, persmaterial pm WHERE p.persid=pc.persid AND (pc.colorid=1 OR pc.colorid=2) AND p.persid=pm.persid AND pm.materialid=2 GROUP BY p.persid HAVING (count(DISTINCT pc.colorid)=2 AND count(DISTINCT pm.materialid)=1)) UNION
(SELECT p.persid FROM person p, perscolor pc, persmaterial pm WHERE p.persid=pc.persid AND (pc.colorid=2 OR pc.colorid=3) AND p.persid=pm.persid AND pm.materialid=2 GROUP BY p.persid HAVING (count(DISTINCT pc.colorid)=2 AND count(DISTINCT pm.materialid)=1))
Remarks:
*I do not see how to turn a general pseudo query into a query like the one in option 1, except for turning the pseudo query into a sum of products form where the sulms would correspond to the UNIONs. IS there a clever way to obtain such a sum of products form from an arbitrary pseudo query?


Option 2:
SELECT persid FROM person p WHERE
(EXISTS(SELECT * FROM perscolor pc WHERE pc.colorid=1 AND p.persid=pc.persid)
OR
EXISTS(SELECT * FROM perscolor pc WHERE pc.colorid=3 AND p.persid=pc.persid))
AND
EXISTS(SELECT * FROM perscolor pc WHERE pc.colorid=2 AND p.persid=pc.persid)
AND
EXISTS(SELECT * FROM persmaterial pm WHERE pm.materialid=2 AND p.persid=pm.persid)
Remarks:
*very easy to get from pseudo query to MySQL query but what about performance?

Option 3:
SELECT p.persid FROM person p, perscolor pc, persmaterial pm WHERE
p.persid=pc.persid
AND
(pc.colorid=1 OR pc.colorid=2 OR pc.colorid=3)
AND p.persid=pm.persid
AND pm.materialid=2
GROUP BY p.persid HAVING
sum(case when pc.colorid in (&#391;',&#393;') then 1 else 0 end) >= 1
AND
sum(case when pc.colorid=&#392;' then 1 else 0 end)>=1
AND
sum(case when pm.materialid=&#392;' then 1 else 0 end)>=1
Remarks:
*this option requires the pseudo query to be turned into a product of sums form; again is their a clever way to obtain such a form;




Option 4
SELECT DISTINCT pc1.persid FROM perscolor pc1
INNER JOIN perscolor pc2
ON pc1.persid=pc2.persid AND pc2.colorid=2
INNER JOIN persmaterial pm1
ON pc1.persid=pm1.persid AND pm1.materialid=2
LEFT OUTER JOIN perscolor pc3
ON pc1.persid=pc3.persid AND pc3.colorid=1
LEFT OUTER JOIN perscolor pc4
ON pc1.persid=pc4.persid AND pc4.colorid=3
WHERE COALESCE(pc3.persid,pc4.persid) IS NOT NULL
Remarks:
*this option requires the pseudo query to be turned into a product of sums form

Option 5:
SELECT p.persid FROM person p, persmaterial pm,perscolor pc1,perscolor pc2,perscolor pc3 WHERE p.persid=pm.persid AND p.persid=pc1.persid AND p.persid=pc2.persid AND p.persid=pc3.persid AND (pc1.colorid=1 OR pc2.colorid=3) AND pc3.colorid=2 AND pm.materialid=2 GROUP BY p.persid
Remarks:
*very easy to get from pseudo query to MySQL query but what about performance?



-- phpMyAdmin SQL Dump
-- version 2.6.1
-- http://www.phpmyadmin.net
--
-- Host: localhost
-- Generation Time: Oct 19, 2006 at 01:13 PM
-- Server version: 4.1.9
-- PHP Version: 4.3.10
--
-- Database: `aston`
--

-- --------------------------------------------------------

--
-- Table structure for table `color`
--

CREATE TABLE `color` (
`colorid` int(11) NOT NULL auto_increment,
`color` varchar(30) NOT NULL default '',
PRIMARY KEY (`colorid`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;

--
-- Dumping data for table `color`
--

INSERT INTO `color` VALUES (1, 'red');
INSERT INTO `color` VALUES (2, 'green');
INSERT INTO `color` VALUES (3, 'blue');
INSERT INTO `color` VALUES (4, 'yellow');

-- --------------------------------------------------------

--
-- Table structure for table `material`
--

CREATE TABLE `material` (
`materialid` int(11) NOT NULL auto_increment,
`material` varchar(30) NOT NULL default '',
PRIMARY KEY (`materialid`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;

--
-- Dumping data for table `material`
--

INSERT INTO `material` VALUES (1, 'wood');
INSERT INTO `material` VALUES (2, 'iron');

-- --------------------------------------------------------

--
-- Table structure for table `perscolor`
--

CREATE TABLE `perscolor` (
`perscolorid` int(11) NOT NULL auto_increment,
`persid` int(11) NOT NULL default &#390;',
`colorid` int(11) NOT NULL default &#390;',
PRIMARY KEY (`perscolorid`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ;

--
-- Dumping data for table `perscolor`
--

INSERT INTO `perscolor` VALUES (1, 1, 1);
INSERT INTO `perscolor` VALUES (2, 1, 2);
INSERT INTO `perscolor` VALUES (3, 2, 1);
INSERT INTO `perscolor` VALUES (5, 3, 3);
INSERT INTO `perscolor` VALUES (6, 3, 2);

-- --------------------------------------------------------

--
-- Table structure for table `persmaterial`
--

CREATE TABLE `persmaterial` (
`persmatid` int(11) NOT NULL auto_increment,
`persid` int(11) NOT NULL default &#390;',
`materialid` int(11) NOT NULL default &#390;',
PRIMARY KEY (`persmatid`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=6 ;

--
-- Dumping data for table `persmaterial`
--

INSERT INTO `persmaterial` VALUES (1, 1, 1);
INSERT INTO `persmaterial` VALUES (2, 1, 2);
INSERT INTO `persmaterial` VALUES (3, 2, 1);
INSERT INTO `persmaterial` VALUES (5, 3, 2);

-- --------------------------------------------------------

--
-- Table structure for table `person`
--

CREATE TABLE `person` (
`persid` int(11) NOT NULL auto_increment,
`name` varchar(30) NOT NULL default '',
PRIMARY KEY (`persid`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;

--
-- Dumping data for table `person`
--

INSERT INTO `person` VALUES (1, 'john');
INSERT INTO `person` VALUES (2, 'emily');
INSERT INTO `person` VALUES (3, 'liz');

Simple Sql Question: Using A Query Result As A Query Variable
EDIT: it works now, I had an error in my code, not my method.

I have a very simple question.

I have 2 tables: 'users' and 'posts' with the following structure:

users: id, username, email_address
posts: id, user_id, post_title, post_text

in a my own mind's mysql, I would like to:

SELECT posts.id, posts.user_id, posts.post_title, posts.post_text users.username FROM users, posts WHERE posts.user_id = users.id

I usually do one query for the post data, and then, based on the use_id record, do another of the users table, but today, I'm being forced to do them in one swoop.

Query Based On Results Of A Previous Query
So far I have managed to construct one query which gives me all individuals that have one of three titles.

based on this I now want to find all the individuals that are affiliated to those listed in the first query ....

Big Query - Query Not Completely Stored In Memory
I have this query and when executed in mySQL query window throws error that "Big Query - Query not completely stored in memory". Also executed thru app, the program justs hangs. I have checked all indexes, they all look good.....

Pagination W/1 Query + How To Use Query With Indexes
i'm asking 2 questions in 1 thread because i don't wanna take up too much room, hopefully no one will mind.

i have mysql 4.1.10

1) i want to find all the rows that were edited this month. the query i currently have ( MONTH(CURDATE()) = MONTH(date) ) doesn't use indexes. how can i manipulate it so i can take advantage of indexes.

2) this is something i've always wondered, but usually just assumed was not possible. if i am listing some results, say 20 per page, how can i get both the total number of results as well as the 20 items required for that specific page. say there are 2 million total results, so grabbing them all and showing just 20 is not an option. if this is not possible what is the most efficient way of making both queries?

Reusing A Query Output In The Same Query
I am guessing a basic question but not one I can find an obvious answer to.

If I create a calculated or modified column in a query (such as a modified text string), and then want to reuse that in the same query as I need to do three or four operations on it in sequence, how do I do it in mySQL 4.1?

Do I need to create a new column to store the interim result in an existing table (and then clear or alter it each time I run the query), or create a temporary table, or is there an easy way to reuse the query output in the same query (does the query have a name like a table name)?

If it requires a new column or table, are there particular disciplines to ensure it is robust and self maintaining?

Possible To Execute A Saved Query From Within Another Query?
Does MySQL provide a way to refer in a query to stored query instruction as if it were an existing table, in such a way that the stored query is exected when the query that refers to it is executed?

Select Query With Sub-query For Count And Max
I have a table "test"... as below... I want to have a result set of all the parents with the count of their children and the lastest created date of their child ...

Create Single Query From Queries On Two Tables (was "Help With Query...")
I read from other thread that query inside loop is not good idea. May I ask some help how can I create a single query to the following code which I use loop.

$sql = "SELECT * FROM mytable order by points desc limit 10";
$rec = mysql_query($sql) or die(mysql_error());
$datas = mysql_fetch_array($rec);

do{
$sq = "Select * from secondtable where linkid = '$datas[id]'";
$rst = mysql_query($sq) or die(mysql_error());
$rows = mysql_fetch_array($rst);
echo "$rows[somefield]";
}while($datas= mysql_fetch_array($rec));
This works perfectly but I want the second query to be out of the loop if there is a way and how.

Grab 'title' From The Table 'forum' Within The Same Query (was "Help With Query")
I have the following query for my vBulletin database:
PHP

$get_stats_newthreads = $db->query_read("    SELECT thread.forumid, thread.postuserid, thread.postusername, thread.threadid, thread.title, thread.lastpost, thread.forumid, thread.replycount, thread.lastposter, thread.dateline, thread.iconid, thread.views, IF(views<=replycount, replycount+1, views) AS views, thread.visible    FROM " . TABLE_PREFIX . "thread AS thread    WHERE NOT ISNULL(thread.threadid) AND $weekold<lastpost AND thread.visible!=0 AND (forumid=34 OR forumid=7 OR forumid=8 OR forumid=11 OR forumid=10)    ORDER BY rand() DESC LIMIT 5");

and would like to grab 'title' from the table 'forum' where forum.forumid=thread.forumid

Using A Query Result In Another Query
Can I use the results of a SELECT query as a "table" in another query?

I want to let my user pick a subset of the data, then refine it further. So ... do I have to repeat all the selection criteria at each step, or can I just do refer to the last query result?

If so, what's the PHP syntax for this?


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