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SQLAuthority News – Resolution for New Year 2011

- by pinaldave

Today is the first day of the year so I want to write something very light. Last Year: 2010 Last Year was a blast; really traveled a lot. My family and I went on vacation. There I enjoyed being father, rolling on the floor and playing with my daughter. Here is the list of the countries I visited throughout 2010: Singapore (twice) Malaysia (twice) Sri Lanka (thrice) Nepal (once) United States of America (twice) United Arab Emirates (UAE) (once) My daughter who just completed 1 year on September 1, 2010 has so far visited three countries: Singapore, Malaysia and Sri Lanka, where I have done lots of community activities. The list containing all my activities can be found at Pinal Dave’s Community Events. I have written nearly 380 blog posts last year. It would be difficult for me to pick a few. However, I keep a running list of all of my articles over here: All Articles on SQLAuthority.com. I have so far received more than 10,000 email questions during the year and consequently I have done my best to answer most of them. I strongly believe if one would Search SQLAuthority.com blog, they would have found the answer quickly. The best part of 2010 for me was working on SQL Server Health Check and SQL Server Performance Tuning. This Year: 2011 This year, I came up with two simple goals: 1. Personal Goal: Reduce Weight 2. Professional Goal: Stay busy for the entire year with SQL Server Performance Tuning Projects. (Currently January 2011 is booked with performance tuning projects and 40 other days are already booked throughout the year). Future The future is something one cannot exactly guess and one cannot see. I just want to wish all of you the very best for this coming New Year. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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Slow MySQL Query Breaking my back!

- by Chris n

so, I have tried everything I can think of, and can't get this query to happen in less than 3 seconds on my local server. I know the problem has to do with the OR referencing both the owner_id and the person_id. if I run one or the other it happens instantly, but together with an or I can't seem to make it work - I looked into rewriting the code, but the way the app was designed it won't be easy. is there a way I can call an equivalent or that won't take so long? here is the sql: SELECT event_types.name as event_type_name,event_types.id as id, count(events.id) as count,sum(events.estimated_duration) as time_sum FROM events,event_types WHERE event_types.id = events.event_type_id AND events.event_type_id != '4' AND ( events.status!='cancelled') AND events.event_type_id != 64 AND ( events.owner_id = 161 OR events.person_id = 161 ) GROUP BY event_types.name ORDER BY event_types.name DESC; Here's the Explain soup, although I'm guessing it's unnecessary cause there is probably a better way to structure that or that is obvious: thanks so much! chris. +----+-------------+-------------+-------+---------------------------------------------------------------------------------------------------------+-------------------------------+---------+-------------------------------------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------------+-------+---------------------------------------------------------------------------------------------------------+-------------------------------+-- | 1 | SIMPLE | event_types | range | PRIMARY | PRIMARY | 4 | NULL | 78 | Using where; Using temporary; Using filesort | | 1 | SIMPLE | events | ref | index_events_on_status,index_events_on_event_type_id,index_events_on_person_id,index_events_on_owner_id | index_events_on_event_type_id | 5 | thenumber_production.event_types.id | 907 | Using where | +----+-------------+-------------+-------+---------------------------------------------------------------------------------------------------------+-------------------------------+---------+-------------------------------------+------+----------------------------------------------+

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Help with MySQL query - Product orders report without duplicate shipping charges

- by Paul

Hello, I have an issue creating a custom report for an e-commerce store running on osCommerce. The client wants the report to have the following columns: Date, Order ID, Product Class, Product Price, Product Tax, Shipping, Order Total The criteria for generating the report are Date Range and Product Class (Textbooks for example) The client wants the report to list each Textbook purchased on its own line. Orders with multiple textbooks would display a separate line for each Textbook in the order. I have it all working except for one part: the shipping amount is order-specific (based on the order total), not product-specific, and is displaying for each product. I need it to display only for the first product of each order, so it is not counted more than once. My current query is: SELECT op.date_funds_captured as 'Date', op.orders_id as 'Order ID', pc.class as 'Product Class', round(op.products_price,2) as 'Product Price', round(op.products_tax*op.products_price/100,2) as 'Product Tax', round(otship.value,2) as 'Shipping', round(ot.value,2) as 'Order Total' from orders_products op, orders_total ot, orders_total otship, productclasses pc, products p where ot.orders_id = op.orders_id and ot.class='ot_total' and op.orders_id = otship.orders_id and otship.class = 'ot_shipping' and p.products_class_id = pc.id and op.products_id = p.products_id and pc.id = 1 pc.id = 1 -- Product class = Textbook Here is an example of the current report output. You can see the problem with order 2256 showing the shipping value three times instead of once: Date Order Product Class Price Tax Shipping Total 2010-01-04 2253 Textbook 24.95 2.43 10.03 37.41 2010-01-04 2256 Textbook 34.95 0.00 18.09 240.37 2010-01-04 2256 Textbook 55.50 0.00 18.09 240.37 2010-01-04 2256 Textbook 36.95 0.00 18.09 240.37 2010-01-04 2258 Textbook 55.50 5.41 12.17 124.24 Please help!!! Thanks, Paul

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Command-Query-Separation and multithreading safe interfaces

- by Tobias Langner

I like the command query separation pattern (from OOSC / Eiffel - basically you either return a value or you change the state of the class - but not both). This makes reasoning about the class easier and it is easier to write exception safe classes. Now, with multi threading, I run into a major problem: the separation of the query and the command basically invalidates the result from the query as anything can happen between those 2. So my question is: how do you handle command query separation in an multi-threaded environment? Clarification example: A stack with command query separation would have the following methods: push (command) pop (command - but does not return a value) top (query - returns the value) empty (query) The problem here is - I can get empty as status, but then I can not rely on top really retrieving an element since between the call of empty and the call of top, the stack might have been emptied. Same goes for pop & top. If I get an item using top, I can not be sure that the item that I pop is the same. This can be solved using external locks - but that's not exactly what I call threadsafe design.

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SQLAuthority News – Presenting at Tech-Ed On Road – Ahmedabad – June 11, 2011 – Wait Types and Queues

- by pinaldave

I will be presenting in person on the subject SQL Server Wait Types and Queues at Ahmedabad on June 11, 2011. Here is the quick summary of the session. SQL Server Waits and Queues – Your Gateway to Perf. Troubleshooting Time: 11:15am – 12:15pm – June 11, 2011 Just like a horoscope, SQL Server Waits and Queues can reveal your past, explain your present and predict your future. SQL Server Performance Tuning uses the Waits and Queues as a proven method to identify the best opportunities to improve performance. A glance at Wait Types can tell where there is a bottleneck. Learn how to identify bottlenecks and potential resolutions in this fast paced, advanced performance tuning session. This session is based on my performance tuning Wait Types and Queues series. SQL SERVER – Summary of Month – Wait Type – Day 28 of 28 During the session there will be Quiz and those who gets right answer will get very interesting gifts from me. Do not miss a single minute of the event. We are also going to have two rock star speakers – Harish Vaidyanathan and Jacob Sebastian. Here is the details for the event: SQLAuthority News – Community Tech Days – TechEd on The Road – Ahmedabad – June 11, 2011 Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology

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How to query collections in NHibernate

- by user305813

Hi, I have a class: public class User { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual IDictionary<string, string> Attributes { get; set; } } and a mapping file: <class name="User" table="Users"> <id name="Id"> <generator class="hilo"/> </id> <property name="Name"/> <map name="Attributes" table="UserAttributes"> <key column="UserId"/> <index column="AttributeName" type="System.String"/> <element column="Attributevalue" type="System.String"/> </map> </class> So now I can add many attributes and values to a User. How can I query those attributes so I can get ie. Get all the users where attributename is "Age" and attribute value is "20" ? I don't want to do this in foreach because I may have millions of users each having its unique attributes. Please help

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conditional update records mysql query

- by Shakti Singh

Hi, Is there any single msql query which can update customer DOB? I want to update the DOB of those customers which have DOB greater than current date. example:- if a customer have dob 2034 update it to 1934 , if have 2068 updated with 1968. There was a bug in my system if you enter date less than 1970 it was storing it as 2070. The bug is solved now but what about the customers which have wrong DOB. So I have to update their DOB. All customers are stored in customer_entity table and the entity_id is the customer_id Details is as follows:- desc customer_entity -> ; +------------------+----------------------+------+-----+---------------------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------------+----------------------+------+-----+---------------------+----------------+ | entity_id | int(10) unsigned | NO | PRI | NULL | auto_increment | | entity_type_id | smallint(8) unsigned | NO | MUL | 0 | | | attribute_set_id | smallint(5) unsigned | NO | | 0 | | | website_id | smallint(5) unsigned | YES | MUL | NULL | | | email | varchar(255) | NO | MUL | | | | group_id | smallint(3) unsigned | NO | | 0 | | | increment_id | varchar(50) | NO | | | | | store_id | smallint(5) unsigned | YES | MUL | 0 | | | created_at | datetime | NO | | 0000-00-00 00:00:00 | | | updated_at | datetime | NO | | 0000-00-00 00:00:00 | | | is_active | tinyint(1) unsigned | NO | | 1 | | +------------------+----------------------+------+-----+---------------------+----------------+ 11 rows in set (0.00 sec) And the DOB is stored in the customer_entity_datetime table the column value contain the DOB. but in this table values of all other attribute are also stored such as fname,lname etc. So the attribute_id with value 11 is DOB attribute. mysql> desc customer_entity_datetime; +----------------+----------------------+------+-----+---------------------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+----------------------+------+-----+---------------------+----------------+ | value_id | int(11) | NO | PRI | NULL | auto_increment | | entity_type_id | smallint(8) unsigned | NO | MUL | 0 | | | attribute_id | smallint(5) unsigned | NO | MUL | 0 | | | entity_id | int(10) unsigned | NO | MUL | 0 | | | value | datetime | NO | | 0000-00-00 00:00:00 | | +----------------+----------------------+------+-----+---------------------+----------------+ 5 rows in set (0.01 sec) Thanks.

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Query Access and VB.NET

- by yae

Hi all: I have 2 tables: "products" and "pieces" PRODUCTS idProd product price PIECES id idProdMain idProdChild quant idProdMain and idProdChild are vinculated with the table: "products". Other considerations is that 1 product can have some pieces and 1 product can be a piece. Price product equal a sum of quantity * price of all their pieces. EXAMPLE: TABLE PRODUCTS (idProd - product - price) 1 - Computer - 300€ 2 - Hard Disk - 100€ 3 - Memory - 50€ 4 - Main Board - 100€ 5 - Software - 50€ 6 - CDroms 100 un. - 30€ TABLE PIECES (id - idProdMain - idProdChild - Quant.) 1 - 1 - 2 - 1 2 - 1 - 3 - 2 3 - 1 - 4 - 1 WHAT I NEED? I need update the price of the main product when the price of the product child (piece) is changed. Following the previous example, if I change the price of this product "memory" (is a piece too) to 60€, then product "Computer" will must change his price to 320€ How I can do it using queries? Already I have tried this to obatin the price of the main product, but not runs. This query not returns any value SELECT Sum(products.price*pieces.quant) AS Expr1 FROM products LEFT JOIN pieces ON (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdMain) WHERE (((pieces.idProdMain)=5));

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Can't return a List from a Compiled Query.

- by Andrew

I was speeding up my app by using compiled queries for queries which were getting hit over and over. I tried to implement it like this: Function Select(ByVal fk_id As Integer) As List(SomeEntity) Using db As New DataContext() db.ObjectTrackingEnabled = False Return CompiledSelect(db, fk_id) End Using End Function Shared CompiledSelect As Func(Of DataContext, Integer, List(Of SomeEntity)) = _ CompiledQuery.Compile(Function(db As DataContext, fk_id As Integer) _ (From u In db.SomeEntities _ Where u.SomeLinkedEntity.ID = fk_id _ Select u).ToList()) This did not work and I got this error message: Type : System.ArgumentNullException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 Message : Value cannot be null. Parameter name: value However, when I changed my compiled query to return IQueryable instead of List like so: Function Select(ByVal fk_id As Integer) As List(SomeEntity) Using db As New DataContext() db.ObjectTrackingEnabled = False Return CompiledSelect(db, fk_id).ToList() End Using End Function Shared CompiledSelect As Func(Of DataContext, Integer, IQueryable(Of SomeEntity)) = _ CompiledQuery.Compile(Function(db As DataContext, fk_id As Integer) _ From u In db.SomeEntities _ Where u.SomeLinkedEntity.ID = fk_id _ Select u) It worked fine. Can anyone shed any light as to why this is? BTW, compiled queries rock! They sped up my app by a factor of 2.

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Help Me With This Access Query

- by yae

I have 2 tables: "products" and "pieces" PRODUCTS idProd product price PIECES id idProdMain idProdChild quant idProdMain and idProdChild are related with the table: "products". Other considerations is that 1 product can have some pieces and 1 product can be a piece. Price product equal a sum of quantity * price of all their pieces. "Products" table contains all products (p EXAMPLE: TABLE PRODUCTS (idProd - product - price) 1 - Computer - 300€ 2 - Hard Disk - 100€ 3 - Memory - 50€ 4 - Main Board - 100€ 5 - Software - 50€ 6 - CDroms 100 un. - 30€ TABLE PIECES (id - idProdMain - idProdChild - Quant.) 1 - 1 - 2 - 1 2 - 1 - 3 - 2 3 - 1 - 4 - 1 WHAT I NEED? I need update the price of the main product when the price of the product child (piece) is changed. Following the previous example, if I change the price of this product "memory" (is a piece too) to 60€, then product "Computer" will must change his price to 320€ How I can do it using queries? Already I have tried this to obatin the price of the main product, but not runs. This query not returns any value: SELECT Sum(products.price*pieces.quant) AS Expr1 FROM products LEFT JOIN pieces ON (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdMain) WHERE (((pieces.idProdMain)=5)); MORE INFO The table "products" contains all the products to sell that it is in the shop. The table "pieces" is to take a control of the compound products. To know those who are the products children. For example of compound product: computers. This product is composed by other products (motherboard, hard disk, memory, cpu, etc.)

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SQL Query with multiple values in one column

- by lp1

I've been beating my head on the desk tring to figure this one out. I have a table that stores job information, and reasons for a job not being completed. The reasons are numeric,01,02,03,etc. You can have two reason for a pending job. If you select two reasons, they are stored in the same column, seperated by a comma. This is anExample from the JOBID table: Job_Number User_Assigned PendingInfo 1 user1 01,02 Now, there is another table named Pending, that stores what those values actually represent. 01=Not enough info, 02=Not enough time, 03=Waiting Review. Example: Pending_Num PendingWord 01 Not Enough Info 02 Not Enough Time What I'm trying to do is query the database to give me all the job numbers, users, pendinginfo, and pending reason. I can break out the first value, but can't figure out how to do the second. What my limited skills have so far: *select Job_number,user_assigned,SUBSTRING(pendinginfo,0,3),pendingword from jobid,pending where SUBSTRING(pendinginfo,0,3)=pending.pending_num and pendinginfo!='00,00' and pendinginfo!='NULL'* What I would like to see for this example would be: Job_Number User_Assigned PendingInfo PendingWord PendingInfo PendingWord 1 User1 01 Not Enough Info 02 Not Enough Time Thanks in advance

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XPATH Query: How to get two elements?

- by Damiano

Hello My HTML code is: <table> <tr> <td class="data1"><p>1</td></td> <td class="data1"><p>2</td></td> <td class="data1"><p>3</td></td> <td class="data1"><p>4</td></td> </tr> <tr> <td class="data1"><p>5</td></td> <td class="data1"><p>6</td></td> <td class="data1"><p>7</td></td> <td class="data1"><p>8</td></td> </tr> </table> My query is: xpath='//tr//td[@class="data1"][4]/p' The results is: <p>4</p> <p>8</p> The results is correct! but, if I want to get example: <p>3</p> <p>4</p> <p>7</p> <p>8</p> So [3]/p and [4]/p How to get these two elements each <tr> ? Thank you so much!

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Please help optimizing a long running query (left outer join, with 2 subqueries)

- by 46and2

Hi all. The query I need help with is: SELECT d.bn, d.4700, d.4500, ... , p.`Activity Description` FROM ( SELECT temp.bn, temp.4700, temp.4500, .... FROM `tdata` temp GROUP BY temp.bn HAVING (COUNT(temp.bn) = 1) ) d LEFT OUTER JOIN ( SELECT temp2.bn, max(temp2.FPE) AS max_fpe, temp2.`Activity Description` FROM `pdata` temp2 GROUP BY temp2.bn ) p ON p.bn = d.bn; The ... represents other fields that aren't really important to solving this problem. The issue is on the the second subquery - it is not using the index I have created and I am not sure why, it seems to be because of the way TEXT fields are handled. The first subquery uses the index I have created and runs quite snappy, however an explain on the second shows a 'Using temporary; Using filesort'. Please see the indexes I have created in the below table create statements. Can anyone help me optimize this? By way of quick explanation the first subquery is meant to only select records that have unique bn's, the second, while it looks a bit wacky (with the max function there which is not being used in the result set) is making sure that only one record from the right part of the join is included in the result set. My table create statements are CREATE TABLE `tdata` ( `BN` varchar(15) DEFAULT NULL, `4000` varchar(3) DEFAULT NULL, `5800` varchar(3) DEFAULT NULL, .... KEY `BN` (`BN`), KEY `idx_t3010`(`BN`,`4700`,`4500`,`4510`,`4520`,`4530`,`4570`,`4950`,`5000`,`5010`,`5020`,`5050`,`5060`,`5070`,`5100`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 CREATE TABLE `pdata` ( `BN` varchar(15) DEFAULT NULL, `FPE` datetime DEFAULT NULL, `Activity Description` text, .... KEY `BN` (`BN`), KEY `idx_programs_2009` (`BN`,`FPE`,`Activity Description`(100)) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 Thanks!

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Complex SQL query, one to many relationship

- by Ethan

Hey SO, I have a query such that I need to get A specific dog All comments relating to that dog The user who posted each comment All links to images of the dog the user who posted each link I've tried a several things, and can't figure out quite how to work it. Here's what I have (condensed so you don't have to wade through it all): SELECT s.dog_id, s.name, c.comment, c.date_added AS comment_date_added, u.username AS comment_username, u.user_id AS comment_user_id, l.link AS link, l.date_added AS link_date_added, u2.username AS link_username, u2.user_id AS link_user_id FROM dogs AS d LEFT JOIN comments AS c ON c.dog_id = d.dog_id LEFT JOIN users AS u ON c.user_id = u.user_id LEFT JOIN links AS l ON l.dog_id = d.dog_id LEFT JOIN users AS u2 ON l.user_id = u2.user_id WHERE d.dog_id = '1' It's sorta close to working, but it'll only return me the first comment, and the first link all as one big array with all the info i requested. The are multiple comments and links per dog, so I need it to give me all the comments and all the links. Ideally it'd return an object with dog_id, name, comments(an array of the comments), links(an array of the links) and then comments would have a bunch of comments, date_added, username, and user_id and links would have a bunch of links with link, date_added, username and user_id. It's got to work even if there are no links or comments. I learned the basics of mySQL somewhat recently, but this is pretty far over my head. Any help would be wonderful. Thanks!

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Web page database query optimization

- by morpheous

I am putting together a web page which is quite 'expensive' in terms of database hits. I don't want to start optimizing at this stage - though with me trying to hit a deadline, I may end up not optimizing at all. Currently the page requires 18 (that's right eighteen) hits to the db. I am already using joins, and some of the queries are UNIONed to minimize the trips to the db. My local dev machine can handle this (page is not slow) however, I feel if I release this into the wild, the number of queries will quickly overwhelm my database (MySQL). I could always use memcache or something similar, but I would much rather continue with my other dev work that needs to be completed before the deadline - at least retrieving the page works - its simply a matter of optimization now (if required). My question therefore is - is 18 db queries for a single page retrieval completely outrageous - (i.e. I should put everything on hold and optimize the hell of the retrieval logic), or shall I continue as normal, meet the deadline and release on schedule and see what happens? [Edit] Just to clarify, I have already done the 'obvious' things like using (single and composite) indexes for fields used in the queries. What I haven't yet done is to run a query analyzer to see if my indexes etc are optimal.

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Overlap of the variable in mysql, my column are set to my query result

- by foodil

The question is not clear , let me clarify it: try{ $sql = ' SELECT UserID <==== (***********Used here for query ******) FROM user WHERE Rights != ?'; $stmt = $conn->prepare($sql); $stmt->execute(array('admin')); $result= $stmt->fetchAll(); } catch(PDOException $e) { die ($e->getMessage().'<a href="add.php"> Back</a>'); } foreach ($result as $set) { if ($set['UserID']==$_SESSION['username']) $rights='edit'; else {$rights=$_POST[$set['UserID']];} if (($rights != 'default' || $set['UserID']==$_SESSION['username']) && $_POST['public']==0 ) { $user=$set['UserID']; try { $query="INSERT INTO user_list(UserID <==== (***********Used here for insert ******),ListID,UserRights) VALUES ($user,$lastID,$rights)"; $stmt = $conn->prepare($query); $stmt->execute(); } catch(PDOException $e) { die ($e->getMessage().'<a href="add.php"> Back</a>'); $conn->rollBack(); } } } As you can see the UserID is a query result but it is also the column i need to insert, so when i insert into the table it will casued an error SQLSTATE[42S22]: Column not found: 1054 Unknown column 'UserA_ID' in 'field list' because the column is modify by my query result from: $query="INSERT INTO user_list(UserID,ListID,UserRights) VALUES ($user,$lastID,$rights)"; to: $query="INSERT INTO user_list(query_result_id,ListID,UserRights) VALUES ($user,$lastID,$rights)"; How to fix it ?Thank you.

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MySQL query pulling from two tables, display in correct fields

- by Matt Nathanson

I'm trying to select all fields in two separate tables as long as they're sharing a common ID. //mysql query $result = mysql_query("SELECT * FROM project, links WHERE project.id = links.id and project.id = $clientID") //displaying the link if ($row['url'] != null){ echo "<div class='clientsection' id='links'>Links</div>"; echo "<a class='clientlink' id='link1' href='" . $row['url'] . "'>" . $row['name'] . "</a>"; } else { echo "<a class='clientlink' id='link1' href='" . $row['url'] . "' style='display:none;'>" . $row['name'] . "</a>"; }; As you can see, my tables are "projects", and "links" Each is sharing a common field "id" for reference. It looks as though where both links.id and project.id are equal, it outputs anything, but when there is no links.id associated with a given $clientID the container relative to the $clientID doesn't display at all. Essentially I'm using this to add links dynamically to a specific client in this CMS and if there are no links, I want the container to show up anyway. Hopefully I've expressed myself clearly, any pointers in the right direction are appreciated. Thanks!

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SQL query for selecting the firsts in a series by cloumn

- by SP

I'm having some trouble coming up with a query for what I am trying to do. I've got a table we'll call 'Movements' with the following columns: RecID(Key), Element(f-key), Time(datetime), Room(int) The table is holding a history of Movements for the Elements. One record contains the element the record is for, the time of the recorded location, and the room it was in at that time. What I would like are all records that indicate that an Element entered a room. That would mean the first (by time) entry for any element in a series of movements for that element in the same room. The input is a room number and a time. IE, I would like all of the records indicating that any Element entered room X after time Y. The closest I came was this Select Element, min(Time) from Movements where Time > Y and Room = x group by Element This will only give me one room entry record per Element though (If the Element has entered the room X twice since time Y I'll only get the first one back) Any ideas? Let me know if I have not explained this clearly. I'm using MS SQLServer 2005.

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NHibernate complex order query

- by manu08

Here's my simplified domain public class Notification { public Guid ID { get; set; } public string Name { get; set; } public IEnumerable<Location> Locations { get; set; } } public class Location { public Guid Id { get; set; } public string Name { get; set; } public decimal Longitude { get; set; } public decimal Latitude { get; set; } } Notifications and Locations have a many-to-many relationship (defined in table LocationsOnNotification). What I'd like to do is query for the nearest 10 Notifications from a given longitude and latitude. I've been trying to use ICriteria, but I'm not sure how to specify the ordering correctly: return Session.CreateCriteria<Notification>() .SetFirstResult(firstIndex) .SetMaxResults(maxResults) .AddOrder(Order.Asc( WHAT GOES HERE! )) .List<Notification>(); What I've been thinking of so far is adding a formula property to the Location mapping; something like this: <property name='Distance' formula='lots of geometry'/> But I'm not sure if that can take in parameters (since I'd need to pass in the user's location to calculate the distance), plus I'm not sure how to specify it in the Order.Asc clause given that it's a property on a many-to-many association class. Any ideas? Or perhaps I should take a different approach altogether. Thanks in advance!

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MYSQL DELETE from a table [closed]

- by Hossein

Possible Duplicate: MySQL DELETE in a single table Hi, I have this table: userurltag(id,user,Url,tag) I want to remove rows that contain urls that are used by only one user, can someone help me? It seems that DELETE...(SELECT...) is not supported in Mysql.

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SQL Query Math Gymnastics

- by keruilin

I have two tables of concern here: users and race_weeks. User has many race_weeks, and race_week belongs to User. Therefore, user_id is a fk in the race_weeks table. I need to perform some challenging math on fields in the race_weeks table in order to return users with the most all-time points. Here are the fields that we need to manipulate in the race_weeks table. races_won (int) races_lost (int) races_tied (int) points_won (int, pos or neg) recordable_type(varchar, Robots can race, but we're only concerned about type 'User') Just so that you fully understand the business logic at work here, over the course of a week a user can participate in many races. The race_week record represents the summary results of the user's races for that week. A user is considered active for the week if races_won, races_lost, or races_tied is greater than 0. Otherwise the user is inactive. So here's what we need to do in our query in order to return users with the most points won (actually net_points_won): Calculate each user's net_points_won (not a field in the DB). To calculate net_points, you take (1000 * count_of_active_weeks) - sum(points__won). (Why 1000? Just imagine that every week the user is spotted a 1000 points to compete and enter races. We want to factor-out what we spot the user because the user could enter only one race for the week for 100 points, and be sitting on 900, which we would skew who actually EARNED the most points.) This one is a little convoluted, so let me know if I can clarify further.

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How do I write this MySQL query?

- by CT

I am working on an Asset DB using a lamp stack. In this example consider the following 5 tables: asset, server, laptop, desktop, software All tables have a primary key of id, which is a unique asset id. Every object has all asset attributes and then depending on type of asset has additional attributes in the corresponding table. If the type is a server, desktop or laptop it also has items in the software table. Here are the table create statements: // connect to mysql server and database "asset_db" mysql_connect("localhost", "asset_db", "asset_db") or die(mysql_error()); mysql_select_db("asset_db") or die(mysql_error()); // create asset table mysql_query("CREATE TABLE asset( id VARCHAR(50) PRIMARY KEY, company VARCHAR(50), location VARCHAR(50), purchase_date VARCHAR(50), purchase_order VARCHAR(50), value VARCHAR(50), type VARCHAR(50), notes VARCHAR(200))") or die(mysql_error()); echo "Asset Table Created.</br />"; // create software table mysql_query("CREATE TABLE software( id VARCHAR(50) PRIMARY KEY, software VARCHAR(50), license VARCHAR(50))") or die(mysql_error()); echo "Software Table Created.</br />"; // create laptop table mysql_query("CREATE TABLE laptop( id VARCHAR(50) PRIMARY KEY, manufacturer VARCHAR(50), model VARCHAR(50), serial_number VARCHAR(50), esc VARCHAR(50), user VARCHAR(50), prev_user VARCHAR(50), warranty VARCHAR(50))") or die(mysql_error()); echo "Laptop Table Created.</br />"; // create desktop table mysql_query("CREATE TABLE desktop( id VARCHAR(50) PRIMARY KEY, manufacturer VARCHAR(50), model VARCHAR(50), serial_number VARCHAR(50), esc VARCHAR(50), user VARCHAR(50), prev_user VARCHAR(50), warranty VARCHAR(50))") or die(mysql_error()); echo "Desktop Table Created.</br />"; // create server table mysql_query("CREATE TABLE server( id VARCHAR(50) PRIMARY KEY, manufacturer VARCHAR(50), model VARCHAR(50), warranty VARCHAR(50))") or die(mysql_error()); echo "Server Table Created.</br />"; ?> How do I query the database so that if I search by id, I receive all related fields to that asset id? Thank you.

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SQL using sum to count results of multiple subqueries

- by asdas

I have a table with 2 columns: integer and var char. I am given only the integer values but need to do work on the var char (string) values. Given an integer, and a list of other integers (no overlap), I want to find the string for that single integer. Then I want to take that string and do the INSTR command with that string, and all the other strings for all the other integers. Then I want the sum of all the INSTR so the result is one number. So lets say I have int x, and list y=[y0, y1, y2]. I want to do 3 INSTR commands like SUM(INSTR(string for x, string for y0), INSTR(string for x, string for y1), INSTR(string for x, string for y2)) I think im going in the wrong direction, this is what I have. Im not good with sub queries. SELECT SUM ( SELECT INSTR ( SELECT string FROM pages WHERE int=? LIMIT 1, ( SELECT string FROM pages WHERE id=? OR id=? OR id=? LIMIT 3 ) ) )

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Query broke down and left me stranded in the woods

- by user1290323

I am trying to execute a query that deletes all files from the images table that do not exist in the filters tables. I am skipping 3,500 of the latest files in the database as to sort of "Trim" the table back to 3,500 + "X" amount of records in the filters table. The filters table holds markers for the file, as well as the file id used in the images table. The code will run on a cron job. My Code: $sql = mysql_query("SELECT * FROM `images` ORDER BY `id` DESC") or die(mysql_error()); while($row = mysql_fetch_array($sql)){ $id = $row['id']; $file = $row['url']; $getId = mysql_query("SELECT `id` FROM `filter` WHERE `img_id` = '".$id."'") or die(mysql_error()); if(mysql_num_rows($getId) == 0){ $IdQue[] = $id; $FileQue[] = $file; } } for($i=3500; $i<$x; $i++){ mysql_query("DELETE FROM `images` WHERE id='".$IdQue[$i]."' LIMIT 1") or die("line 18".mysql_error()); unlink($FileQue[$i]) or die("file Not deleted"); } echo ($i-3500)." files deleted."; Output: 0 files deleted. Database contents: images table: 10,000 rows filters table: 63 rows Amount of rows in filters table that contain an images table id: 63 Execution time of php script: 4 seconds +/- 0.5 second Relevant DB structure TABLE: images id url etc... TABLE: filter id img_id (CONTAINS ID FROM images table) etc...

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MySQL floating point comparison issues

- by Sharief

I ran into an issue by introducing floating point columns in the MySQL database schema that the comparisons on floating point values don't return the correct results always. 1 - 50.12 2 - 34.57 3 - 12.75 4 - ...(rest all less than 12.00) SELECT COUNT(*) FROM `users` WHERE `points` > "12.75" This returns me "3". I have read that the comparisons of floating point values in MySQL is a bad idea and decimal type is the better option. Do I have any hope of moving ahead with the float type and get the comparisons to work correctly?

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