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  • Find all those columns which have only null values, in a MySQL table

    - by Robin v. G.
    The situation is as follows: I have a substantial number of tables, with each a substantial number of columns. I need to deal with this old and to-be-deprecated database for a new system, and I'm looking for a way to eliminate all columns that have - apparently - never been in use. I wanna do this by filtering out all columns that have a value on any given row, leaving me with a set of columns where the value is NULL in all rows. Of course I could manually sort every column descending, but that'd take too long as I'm dealing with loads of tables and columns. I estimate it to be 400 tables with up to 50 (!) columns per table. Is there any way I can get this information from the information_schema? EDIT: Here's an example: column_a column_b column_c column_d NULL NULL NULL 1 NULL 1 NULL 1 NULL 1 NULL NULL NULL NULL NULL NULL The output should be 'column_a' and 'column_c', for being the only columns without any filled in values.

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  • Having to insert a record, then update the same record warrants 1:1 relationship design?

    - by dianovich
    Let's say an Order has many Line items and we're storing the total cost of an order (based on the sum of prices on order lines) in the orders table. -------------- orders -------------- id ref total_cost -------------- -------------- lines -------------- id order_id price -------------- In a simple application, the order and line are created during the same step of the checkout process. So this means INSERT INTO orders .... -- Get ID of inserted order record INSERT into lines VALUES(null, order_id, ...), ... where we get the order ID after creating the order record. The problem I'm having is trying to figure out the best way to store the total cost of an order. I don't want to have to create an order create lines on an order calculate cost on order based on lines then update record created in 1. in orders table This would mean a nullable total_cost field on orders for starters... My solution thus far is to have an order_totals table with a 1:1 relationship to the orders table. But I think it's redundant. Ideally, since everything required to calculate total costs (lines on an order) is in the database, I would work out the value every time I need it, but this is very expensive. What are your thoughts?

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  • counting employee attendance

    - by jjj
    i am trying to write a statment for counting the employees attendance and execute thier id , name and the days that he has working on the last 3 months by counting the duplicate id on NewTimeAttendance for month 1 , 2 and 3 .. i tried to count : Select COUNT(employeeid) from NewTimeAttendance where employeeid=1 and (month=1 or month =2 or month = 3) This is absolutely working ,but just for one employee... the secound try: SELECT COUNT(NewEmployee.EmployeeID) FROM NewEmployee INNER JOIN NewTimeAttendance ON NewEmployee.EmployeeID = NewTimeAttendance.EmployeeID and (month=1 or month =2 or month = 3) This is working , but it counts all employees .. and i want it to execute each EmployeeId, EmployeeName and number of days as new record last try: (before you see the code ... it is wrong ..but i am trying) for i in 0..27 loop SELECT COUNT(NewEmployee.EmployeeID),NewEmployee.EmployeeId,EmployeeName FROM NewEmployee INNER JOIN NewTimeAttendance ON NewEmployee.EmployeeID(i) = NewTimeAttendance.EmployeeID and (month=1 or month =2 or month = 3) end loop i realy need help...thanks in advance

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  • While Loop in TSQL with Sum totals

    - by RPS
    I have the following TSQL Statement, I am trying to figure out how I can keep getting the results (100 rows at a time), store them in a variable (as I will have to add the totals after each select) and continue to select in a while loop until no more records are found and then return the variable totals to the calling function. SELECT [OrderUser].OrderUserId, ISNULL(SUM(total.FileSize), 0), ISNULL(SUM(total.CompressedFileSize), 0) FROM ( SELECT DISTINCT TOP(100) ProductSize.OrderUserId, ProductSize.FileInfoId, CAST(ProductSize.FileSize AS BIGINT) AS FileSize, CAST(ProductSize.CompressedFileSize AS BIGINT) AS CompressedFileSize FROM ProductSize WITH (NOLOCK) INNER JOIN [Version] ON ProductSize.VersionId = [Version].VersionId ) AS total RIGHT OUTER JOIN [OrderUser] WITH (NOLOCK) ON total.OrderUserId = [OrderUser].OrderUserId WHERE NOT ([OrderUser].isCustomer = 1 AND [OrderUser].isEndOrderUser = 0 OR [OrderUser].isLocation = 1) AND [OrderUser].OrderUserId = 1 GROUP BY [OrderUser].OrderUserId

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  • Oracle global_names DELETE problem

    - by jyzuz
    I'm using a database link to execute a DELETE statement on another DB, but the DB link name doesn't conform to global naming, and this requirement cannot change. Also I have global_names set to false, and cannot be changed either. When I try to use these links however, I receive: ORA-02069: - global_names parameter must be set to TRUE for this operation Cause: A remote mapping of the statement is required but cannot be achieved because GLOBAL_NAMES should be set to TRUE for it to be achieved. - Action: Issue `ALTER SESSION SET GLOBAL_NAMES = TRUE` (if possible) What is the alternative action when setting global_names=true is not possible? Cheers, Jean

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  • Alternative to subqueries

    - by Juanma
    I'm using Mysql 5.1, and have this query, is there a way to not use the subqueries and accomplish the same result? SELECT oref.affiliate_id, ROUND(sum( oph.amount ) * 0.10 ,2) AS tsum FROM operators_referer AS oref LEFT JOIN operators_payments_history AS oph ON oref.operator_id = oph.operator_id WHERE oref.affiliate_id = 28221 AND ( oph.date_paid > ( SELECT MAX(aph.date_paid) FROM affiliates_payments_history AS aph WHERE aph.operator_id = oref.affiliate_id ) OR ( SELECT MAX(aph.date_paid) FROM affiliates_payments_history AS aph WHERE aph.operator_id = oref.affiliate_id ) is NULL )

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  • Joining 3 tables - doing joins how to

    - by Kieran
    This is my current query - its not getting the required result. I want it do display all of the "resources" even if they dont have a connection. SELECT * FROM (`user_permissions`) JOIN `user_groups` ON `user_groups`.`id` = `user_permissions`.`role` JOIN `user_resources` ON `user_resources`.`id` = `user_permissions`.`resource` WHERE `role` = '4' When I try left join or right join it still returns the same result. The result I get is: id | role | resource | name 5 | 4 | 2 | Changelog I want id | role | resource | name 5 | 4 | 2 | Changelog null | null | null | Resource2 null | null | null | Resource3 Is this possible?

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  • How do I all the registered users on a day report

    - by Nadal
    I have a table called users where I have two columns: name and created_at. created_at column column is of type datetime and it stores the datetime when this user was created. I need to know the number of users created for a given date range. Let's say I ask give me user report between 1-nov-2010 and 30-nov-2010 . I need something like this 1-nov-2010: 2 2-nov-2010: 5 The problem I am running into is that created_at data has value upto second. How do I check if a created_at date falls within a given date. Any help in solving this problem is appreciated. I am using mysql5.

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  • MySQL: Limit rows linked to each joined row

    - by SolidSnakeGTI
    Hello, Specifications: MySQL 4.1+ I've certain situation that requires certain result set from MySQL query, let's see the current query first & then ask my question: SELECT thread.dateline AS tdateline, post.dateline AS pdateline, MIN(post.dateline) FROM thread AS thread LEFT JOIN post AS post ON(thread.threadid = post.threadid) LEFT JOIN forum AS forum ON(thread.forumid = forum.forumid) WHERE post.postid != thread.firstpostid AND thread.open = 1 AND thread.visible = 1 AND thread.replycount >= 1 AND post.visible = 1 AND (forum.options & 1) AND (forum.options & 2) AND (forum.options & 4) AND forum.forumid IN(1,2,3) GROUP BY post.threadid ORDER BY tdateline DESC, pdateline ASC As you can see, mainly I need to select dateline of threads from 'thread' table, in addition to dateline of the second post of each thread, that's all under the conditions you see in the WHERE CLAUSE. Since each thread has many posts, and I need only one result per thread, I've used GROUP BY CLAUSE for that purpose. This query will return only one post's dateline with it's related unique thread. My questions are: How to limit returned threads per each forum!? Suppose I need only 5 threads -as a maximum- to be returned for each forum declared in the WHERE CLAUSE 'forum.forumid IN(1,2,3)', how can this be achieved. Is there any recommendations for optimizing this query (of course after solving the first point)? Notes: I prefer not to use sub-queries, but if it's the only solution available I'll accept it. Double queries not recommended. I'm sure there's a smart solution for this situation. Appreciated advice in advance :)

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  • MySQL - Where - search string - MATCH.

    - by Jamie
    Hi guys, Quick question. I'm in a bit of a rush but if someone could quickly point me in the right direction I would be very very happy. I have a field in the db, let's call it field_a which returns a string in the format "20,50,60,80" etc. I wish to do a query which will search in this field to see if 20 exists. Could I use MySQL MATCH or is there a better way? Thank you!

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  • Which MySql line is faster:

    - by Camran
    I have a classified_id variable which matches one document in a MySql table. I am currently fetching the information about that one record like this: SELECT * FROM table WHERE table.classified_id = $classified_id I wonder if there is a faster approach, for example like this: SELECT 1 FROM table WHERE table.classified_id = $classified_id Wont the last one only select 1 record, which is exactly what I need, so that it doesn't have to scan the entire table but instead stops searching for records after 1 is found? Or am I dreaming this? Thanks

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  • How to create unique user key

    - by Grayson Mitchell
    Scenario: I have a fairly generic table (Data), that has an identity column. The data in this table is grouped (lets say by city). The users need an identifier in order for printing on paper forms, etc. The users can only access their cites data, so if they use the identity column for this purpose they will see odd numbers (e.g. a 'New York' user might see 1,37,2028... as the listed keys. Idealy they would see 1,2,3... (or something similar) The problem of course is concurrency, this being a web application you can't just have something like: UserId = Select Count(*)+1 from Data Where City='New York' Has anyone come up with any cunning ways around this problem?

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  • SSAS OLAP MDX and relationships

    - by Sonic Soul
    I new to OLAP, and still not sure how to create a relationship between 2 or more entities. I am basing my cube on views. For simplicity sake let's call them like this: viewParent (ParentID PK) viewChild (ChildID PK, ParentID FK) these views have more fields, but they're not important for this question. in my data source, i defined a relationship between viewParent and viewChild using ParentID for the link. As for measures, i was forced to create separate measures for Parent and Child. in my MDX query however, the relationship does not seem to be enforced. If i select record count for parent, child, and add some filters for the parent, the child count is not reflecting it.. SELECT { [Measures].[ParentCount],[Measures].[ChildCount] } ON COLUMNS FROM [Cube] WHERE { ( {[Time].[Month].&[2011-06-01T00:00:00]} ,{[SomeDimension].&[Foo]} ) } the selected ParentCount is correct, but ChildCount is not affected by any of the filters (because they are parent filters). However, since i defined a relationship, how can i take advantage of that to filter children by parent filter?

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  • Do I need to drop index on temp table?

    - by Phil
    Hi, Fairly simple question, but I don't see it anywhere else on SO: Do indexes (indices?) on a temporary table get automatically deleted with the temporary table? I'd imagine they do but I don't really know how to check to make sure. Thanks, Phil

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  • how do I integrate the aspnet_users table that comes with asp.net membership into my existing databa

    - by ooo
    i have a database that already has a users table COLUMNS: userID - int loginName - string First - string Last - string i just installed the asp.net membership table. Right now all of my tables are joined into my users table foreign keyed into the "userId" field How do i integrate asp.net_users table into my schema? here are the ideas i thought of: Add a membership_id field to my users table and on new inserts, include that new field in my users table. This seems like the cleanest way as i dont need to break any existing relationships. break all existing relationship and move all of the fields in my user table into the asp.net_users table. This seems like a pain but ultimately will lead to the most simple, normalized solution any thoughts?

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  • Running an application from an USB device...

    - by Workshop Alex
    I'm working on a proof-of-concept application, containing a WCF service with console host and client, both on a single USB device. On the same device I will also have the client application which will connect to this service. The service uses the entity framework to connect to the database, which in this POC will just return a list of names. If it works, it will be used for a larger project. Creating the client and service was easy and this works well from USB. But getting the service to connect to the database isn't. I've found this site, suggesting that I should modify machine.config but that stops the XCopy deployment. This project cannot change any setting of the PC, so this suggestion is bad. I cannot create a deployment setup either. The whole thing just needs to run from USB disk. So, how do I get it to run? (The service just selects a list of names from the database, which it returns to the client. If this POC works, it will do far more complex things!)

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  • How can I use an array within a SQL query

    - by ThinkingInBits
    So I'm trying to take a search string (could be any number of words) and turn each value into a list to use in the following IN statement) in addition, I need a count of all these values to use with my having count filter $search_array = explode(" ",$this->search_string); $tag_count = count($search_array); $db = Connect::connect(); $query = "select p.id from photographs p left join photograph_tags c on p.id = c.photograph_id and c.value IN ($search_array) group by p.id having count(c.value) >= $tag_count"; This currently returns no results, any ideas?

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  • multi-row update table with "different" data

    - by kralco626
    I think the best way to explain this is to tell you what I have. I have two tables A and B both have columns Field1 and Field2. However Field 2 is not populated in table B I want to populate field 2 of table B with field 2 of table A where field 1 of table A matches field 1 of table B. something like update tableB set Field2 = tableA.field2 where tablea.field1 = tableb.field1. The reason this may seem so odd and obscure is that I'm tyring to do an inital data load form an old database to a new one. please let me know if you need clarification

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  • MySQL "NULL" questions

    - by Camran
    I have a table with several columns. Sometimes some of these column fields may be empty (ie. I won't use them in some cases). My questions: Would it be smart to set them to NULL in phpmyadmin? What does the "NULL" property actually do? Would I gain anything at all by setting them to NULL? Is it possible to use a NULL field the same way even though it is set to null?

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  • How do I select a random record efficiently in MySQL?

    - by user198729
    mysql> EXPLAIN SELECT * FROM urls ORDER BY RAND() LIMIT 1; +----+-------------+-------+------+---------------+------+---------+------+-------+---------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------------+------+---------+------+-------+---------------------------------+ | 1 | SIMPLE | urls | ALL | NULL | NULL | NULL | NULL | 62228 | Using temporary; Using filesort | +----+-------------+-------+------+---------------+------+---------+------+-------+---------------------------------+ The above doesn't qualify as efficient,how should I do it properly?

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  • Help me choose between XML or SQL Lite on android

    - by Ngetha
    I have an android app that periodically, say once a week downloads content from a server in XML. The content is used by the app, different Acitivities use different parts of the content. My question is a design one, should I save the data in SQlite or just keep it as an XML file, which one would be faster to read? The app can only use one content piece at a time, which means subsequent XML content downloads replace the old one.

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  • Extract time part from TimeStamp column in ORACLE

    - by RRUZ
    Actually i' am using MyTimeStampField-TRUNC(MyTimeStampField) to extract the time part from an timestamp column in Oracle. SELECT CURRENT_TIMESTAMP-TRUNC(CURRENT_TIMESTAMP) FROM DUAL this return +00 13:12:07.100729 this work ok for me, to extract the time part from an timestamp field, but i' m wondering if exist a better way (may be using an built-in function of ORACLE) to do this? Thanks.

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  • Getting the last element of a Postgres array, declaratively

    - by Wojciech Kaczmarek
    How to obtain the last element of the array in Postgres? I need to do it declaratively as I want to use it as a ORDER BY criteria. I wouldn't want to create a special PGSQL function for it, the less changes to the database the better in this case. In fact, what I want to do is to sort by the last word of a specific column containing multiple words. Changing the model is not an option here. In other words, I want to push Ruby's sort_by {|x| x.split[-1]} into the database level. I can split a value into array of words with Postgres string_to_array or regexp_split_to_array functions, then how to get its last element?

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  • Accessing both stored procedure output parameters AND the result set in Entity Framework?

    - by MS.
    Is there any way of accessing both a result set and output parameters from a stored procedure added in as a function import in an Entity Framework model? I am finding that if I set the return type to "None" such that the designer generated code ends up calling base.ExecuteFunction(...) that I can access the output parameters fine after calling the function (but of course not the result set). Conversely if I set the return type in the designer to a collection of complex types then the designer generated code calls base.ExecuteFunction<T>(...) and the result set is returned as ObjectResult<T> but then the value property for the ObjectParameter instances is NULL rather than containing the proper value that I can see being passed back in Profiler. I speculate the second method is perhaps calling a DataReader and not closing it. Is this a known issue? Any work arounds or alternative approaches? Edit My code currently looks like public IEnumerable<FooBar> GetFooBars( int? param1, string param2, DateTime from, DateTime to, out DateTime? createdDate, out DateTime? deletedDate) { var createdDateParam = new ObjectParameter("CreatedDate", typeof(DateTime)); var deletedDateParam = new ObjectParameter("DeletedDate", typeof(DateTime)); var fooBars = MyContext.GetFooBars(param1, param2, from, to, createdDateParam, deletedDateParam); createdDate = (DateTime?)(createdDateParam.Value == DBNull.Value ? null : createdDateParam.Value); deletedDate = (DateTime?)(deletedDateParam.Value == DBNull.Value ? null : deletedDateParam.Value); return fooBars; }

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