select tag - Page 273 - Developer IT

LINQ to Objects .Distinct() not pulling distinct objects

- by Anthony Potts

I have two ways that I am doing a fuzzy search for a customer. One is by an abbreviated name and the other is by the customers full name. When I take these two and then union them together (which I have read several places should remove distinct values) I get duplicates. Thinking that all I need to do is then call the .Distinct() method on this I also still get Duplicates. Do I need to implement some compare functionality in my customer object? My code: Dim shortNameMatch As List(Of ICustomer) = CustomerLibrary.GetCustomersByShortName(term) Dim custNameMatch As List(Of ICustomer) = CustomerLibrary.GetCustomersByCustName(term) Dim allMatch = (From a In (From s In shortNameMatch Select s).Union(From c In custNameMatch Select c) Select a).Distinct()

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PostgreSQL JOIN with array type with array elements order, how to implement?

- by Adiasz

Hello I have two tables in database: CREATE TABLE items( id SERIAL PRIMARy KEY, ... some other fields ); This table contains come data row with unique ID. CREATE TABLE some_choosen_data_in_order( id SERIAL PRIMARy KEY, id_items INTEGER[], ); This table contains array type field. Each row contains values of IDs from table "items" in specyfic order. For example: {2,4,233,5}. Now, I want to get data from table "items" for choosen row from table "some_choosen_data_in_order" with order for elements in array type. The my attempt is JOIN: SELECT I.* FROM items AS I JOIN some_choosen_data_in_order AS S ON I.id = ANY(S.id_items) WHERE S.id = ? Second attempt was subquery like: SELECT I.* FROM items AS I WHERE I.id = ANY (ARRAY[SELECT S.id_items FROM some_choosen_data_in_order WHERE id = ?]) But none of them keep IDs order in array field. Could You help me, how to get data from "items" table with correspond with array IDs order from "some_choosen_data_in_order" table for specyfic row?

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sort the "rollup" in group by

- by shantanuo

I found that the "with rollup" option used with group by is very useful. But it does not behave with "order by" clause. Is there any way to order by the way I want as well as calculate the sub-totals? CREATE TABLE `mygroup` ( `id` int(11) default NULL, `country` varchar(100) default NULL ) ENGINE=MyISAM ; INSERT INTO `mygroup` VALUES (1,'India'),(5,'India'),(8,'India'),(18,'China'),(28,'China'),(28,'China'); mysql>select country, sum(id) from mygroup group by country with rollup; +---------+---------+ | country | sum(id) | +---------+---------+ | China | 74 | | India | 14 | | NULL | 88 | +---------+---------+ 3 rows in set (0.00 sec) mysql>select country, sum(id) as cnt from mygroup group by country order by cnt ; +---------+------+ | country | cnt | +---------+------+ | India | 14 | | China | 74 | +---------+------+ 2 rows in set (0.00 sec) mysql>select country, sum(id) as cnt from mygroup group by country with rollup order by cnt; ERROR 1221 (HY000): Incorrect usage of CUBE/ROLLUP and ORDER BY Expected Result: +---------+------+ | country | cnt | +---------+------+ | India | 14 | | China | 74 | | NULL | 88 | +---------+---------+ 3 rows in set (0.00 sec)

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mysql view performance

- by vamsivanka

I have a table for about 100,000 users in it. First Case: explain select * from users where state = 'ca' when i do an explain plan for the above query i got the cost as 5200 Second Case: Create or replace view vw_users as select * from users Explain select * from vw_users where state = 'ca' when i do an explain plan on the second query i got the cost as 100,000. How does the where clause in the view work ?? Is the where clause applied after the view retrieves all the rows. Please let know, how can i fix this issue. Thanks

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MySQL vs PHP when retrieving a random item

- by andufo

Hi, which is more efficient (when managing over 100K records): A. Mysql SELECT * FROM user ORDER BY RAND(); of course, after that i would already have all the fields from that record. B. PHP use memcached to have $cache_array hold all the data from "SELECT id_user FROM user ORDER BY id_user" for 1 hour or so... and then: $id = array_rand($cache_array); of course, after that i have to make a MYSQL call with: SELECT * FROM user WHERE id_user = $id; so... which is more efficient? A or B?

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Zend Framework - applying order by on a nested query

- by Gublooo

Hey guys This might be a very simple thing. Check out the normal sql query below (select * from shopping order by shopping_id desc limit 5) order by RAND() This query runs successfully in mysql - not sure if this is the right way of doing it - but it works. It gets the last 5 ids from shopping table and randomly orders them everytime I want to achieve this in Zend. I'm not sure how to execute the first part and then apply the RAND clause to the results - what I have below does not do that. $select = $this-select() -from(array('sh'='shopping')) -order('shopping_id desc') -limit(5) -order('RAND()');

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How to get query result even if JOIN hasn't found any results?

- by user1734651

I want select data for user, and join another info from other table that related to the user. The problem is that this extra data not always exist for any user, just for few. How can I write a query that will return NULL for not found data, instead just return null for the whole query? SELECT a.*, b.* FROM user AS a LEFT JOIN extra AS b ON (a.userid = b.userid) WHERE a.userid = {$userid} LIMIT 1 When extra data found for the user, I get the resource as expected. If not, I get NULL for the whole query. Bottom line, I don't care if "extra" exist for the user or not, if yes - select it as well, if not - ignore that.

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using joins or multiple queries in php/mysql

- by askkirati

Here i need help with joins. I have two tables say articles and users. while displaying articles i need to display also the user info like username, etc. So will it be better if i just use joins to join the articles and user tables to fetch the user info while displaying articles like below. SELECT a.*,u.username,u.id FROM articles a JOIN users u ON u.id=a.user_id OR can this one in php. First i get the articles with below sql SELECT * FROM articles Then after i get the articles array i loop though it and get the user info inside each loop like below SELECT username, id FROM users WHERE id='".$articles->user_id."'; Which is better can i have explanation on why too. Thank you for any reply or views

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Implementing a "special" Access database to Expression Web

- by Newbie

I have just got an answer to my question about combining the result of a SQL. This was done with "ConcatRelated". Now I want to implement this in Expression Web 3. The SQL's I used in Access: SELECT land.id, land.official_name, vaksiner.vaksiner FROM land INNER JOIN (vaksiner INNER JOIN land_sykdom ON vaksiner.id = land_sykdom.sykdom) ON land.kort = land_sykdom.land ORDER BY land.official_name; and SELECT DISTINCT id, official_name, ConcatRelated("vaksiner","qryVaksinerRaw","id = " & [id]) AS vaksiner FROM qryVaksinerRaw; The last is saved as vaksine_query This is the SQL that I want to add to Expression Web: SELECT vaksine_query.id, vaksine_query.official_name, vaksine_query.vaksiner FROM vaksine_query WHERE vaksine_query.id="?"; Expression Web gives me the error message "Undefined function 'ContactRelated' in expression.

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appending to cursor in oracle

- by Omnipresent

I asked a question yesterday which got answers but didnt answer the main point. I wanted to reduce amount of time it took to do a MINUS operation. Now, I'm thinking about doing MINUS operation in blocks of 5000, appending each iterations results to the cursor and finally returning the cursor. I have following: V_CNT NUMBER :=0; V_INTERVAL NUMBER := 5000; begin select count(1) into v_cnt from TABLE_1 while (v_cnt > 0) loop open cv_1 for SELECT A.HEAD,A.EFFECTIVE_DATE, FROM TABLE_1 A WHERE A.TYPE_OF_ACTION='6' AND A.EFFECTIVE_DATE >= ADD_MONTHS(SYSDATE,-15) AND A.ROWNUM <= V_INTERVAL MINUS SELECT B.head,B.EFFECTIVE_DATE, FROM TABLE_2 B AND B.ROWNUM <= V_INTERVAL V_CNT := V_CNT - V_INTERVAL; END LOOP; end; However, as you see...in each iteration the cursor is overwritten. How can I change the code so that in each iteration it appends to cv_1 cursor rather than overwriting?

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JPA and MySQL transaction isolation level

- by armandino

I have a native query that does a batch insert into a MySQL database: String sql = "insert into t1 (a, b) select x, y from t2 where x = 'foo'"; EntityTransaction tx = entityManager.getTransaction(); try { tx.begin(); int rowCount = entityManager.createNativeQuery(sql).executeUpdate(); tx.commit(); return rowCount; } catch(Exception ex) { tx.rollback(); log.error(...); } This query causes a deadlock: while it reads from t2 with insert .. select, another process tries to insert a row into t2. I don't care about the consistency of reads from t2 when doing an insert .. select and want to set the transaction isolation level to READ_UNCOMMITTED. How do I go about setting it in JPA?

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filtering for multiple values on one column. All values must exist, else - return zero

- by Andrew

Hello All, I would like to filter one column in a table for couple values and show results only if all those values are there. If one or more is missing, then return zero results. example table +----+--------+----------+ | id | Fruit | Color | +----+--------+----------+ | 1 | apple | red | | 2 | mango | yellow | | 3 | banana | yellow | +----+--------+----------+ example "wrong" code: (this must return 3 rows) select Fruit FROM table WHERE Color = red AND Color = yellow but select Fruit FROM table WHERE Color = red AND Color = green must return 0 rows. (If i use select Fruit FROM table WHERE Color = red OR Color = green i get 1 row which is not what i need) I am using PHP with form where user checks different checkboxes that represent different values of the same column. So when he selects multiple checkboxes, all those values should be in the result set, otherwise no result should be given. Thank you, Andrew

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How do I do this Database Model in Django?

- by alex

Django currently does not support the "Point" datatype in MySQL. That's why I created my own. class PointField(models.Field): def db_type(self): return 'Point' class Tag(models.Model): user = models.ForeignKey(User) utm = PointField() As you can see, this works, and syncdb creates the model fine. However, my current code calculates a length between two Points using raw SQL. cursor.execute("SELECT user_id FROM life_tag WHERE\ (GLength(LineStringFromWKB(LineString(asbinary(utm), asbinary(PointFromWKB(point(%s, %s)))))) < 55)... This says: Select where the length between the given point and the table point is less than 55. How can I do this with Django instead of RAW SQL? I don't want to do cursors and SELECT statements anymore. How can I modify the models.py in order to do this?

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Optimize SQL with Interbase

- by Roland Bengtsson

I was inspired by the good answers from my previous question about SQL. Now this SQL is run on a DB with Interbase 2009. It is about 21 GB in size. SELECT DistanceAsMeters, Bold_Id, Created, AddressFrom.CityName_CO as FromCity, AddressTo.CityName_CO as ToCity FROM AddrDistance LEFT JOIN Address AddressFrom ON AddrDistance.FromAddress = AddressFrom.Bold_Id LEFT JOIN Address AddressTo ON AddrDistance.ToAddress = AddressTo.Bold_Id Where DistanceAsMeters = 0 and PseudoDistanceAsCostKm = 0 and not AddrDistance.bold_id in (select bold_id from DistanceQueryTask) Order By Created Desc There are 840000 rows with AddrDistance 190000 rows with Address and 4 with DistanceQueryTask. The question is, can this be done faster? I guess, the same query is run many times select bold_id from DistanceQueryTask. Note that I'm not interested in stored procedures, just plain SQL :)

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Optimization of running total calculation in SQL for multiple values per join condition

- by Kiril

I have the following table (test_table): date value --------------- d1 10.0 d1 20.0 d2 60.0 d2 10.0 d2 -20.0 d3 40.0 I calculate the running total as follows. I use the same query twice, because first I need to calculate the values for a specifi date, and afterwards I can calculate the running total. Otherwise, joining the two tables where date is not unique, I would get too many results from the join: SELECT t1.date, SUM(t2.value) AS total FROM (SELECT date, SUM(value) AS value FROM test_table GROUP BY date) AS t1 JOIN (SELECT date, SUM(value) AS value FROM test_table GROUP BY date) AS t2 ON t1.date >= t2.date GROUP BY t1.date ORDER BY t1.date This gives me (which is fine): date total ------------- d1 30.0 d2 80.0 d3 120.0 BUT, this query isn't very efficient, because I need to change conditions in two places, if necessary. In production, the test_table is a lot bigger ( 4 Mio. rows), and the query takes too much time to complete. Question: How can I avoid using the same query twice?

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Is 'second' a keyword in mysql full-text searches?

- by Larry

I have a simple MySQL table that is setup for full text search. | id | title | ---------------------- | 1 | test event | | 2 | Second test | | 3 | Larry's event | | 4 | this second | When I use the query: SELECT * FROM EVENTS WHERE MATCH (title) AGAINST ('test event' IN BOOLEAN MODE); I get back 3 rows; the ones containing 'test event', 'Second test', and 'Larry's Event'. Now If I run the following query: SELECT * FROM EVENTS WHERE MATCH (title) AGAINST ('second' IN BOOLEAN MODE); Nothing is returned... strange? Lastly, if I run the query: SELECT * FROM EVENTS WHERE MATCH (title) AGAINST ('second test' IN BOOLEAN MODE); I get back 2 rows; the ones containing 'test event' and 'Second test'. I appears that the word 'second' cannot be searched or needs to be escaped somehow. Am I missing something?

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How to SET ARITHABORT ON for connections in Linq To SQL

- by Laurence

By default, the SQL connection option ARITHABORT is OFF for OLEDB connections, which I assume Linq To SQL is using. However I need it to be ON. The reason is that my DB contains some indexed views, and any insert/update/delete operations against tables that are part of an indexed view fail if the connection does not have ARITHABORT ON. Even selects against the indexed view itself fail if the WITH(NOEXPAND) hint is used (which you have to use in SQL Standard Edition to get the performance benefit of the indexed view). Is there somewhere in the data context I can specify I want this option ON? Or somewhere in code I can do it?? I have managed a clumsy workaround, but I don't like it .... I have to create a stored procedure for every select/insert/update/delete operation, and in this proc first run SET ARITHABORT ON, then exec another proc which contains the actual select/insert/update/delete. In other words the first proc is just a wrapper for the second. It doesn't work to just put SET ARITHABORT ON above the select/insert/update/delete code.

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Binding Linq To Entities query results to a datagridview

- by Nickson

I just started playing with Linq to entities in a windows forms application and am not understanding one behavior that looks so simple though. If i type code below, i get ReadOnly records in my dataGridView Dim x = From n in Table1 _ Select n.FirstName, n.LastName, N.Department DataGridView1.DataSource = x But if i type the following code, i get editable rows in my dataGridView Dim x = From n in Table1 _ Select n DataGridView1.DataSource = x So, basically if i specify the column names to select and databind to my DataGridView1, the rows are readonly but if i do not specify the column names and databind to the DataGridView, the rows are editable and i don't understand why.

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Parameterized SQL statements vs. very simple method

- by Philipp G

When I started to write the first SQL-Statements in my programs I felt quite comfortable with protecting myself against SQL-Injection with a very simple method that a colleague showed me. It replaced all single quotes with two single quotes. So for example there is a searchfield in which you can enter a customername to search in the customertable. If you would enter Peter's Barbershop The SELECT Statement would look like SELECT * FROM Customers WHERE Customername = 'Peter''s Barbershop' If now an attacker would insert this: ';DROP TABLE FOO; -- The statement would look like: SELECT * FROM Customers WHERE Customername = ''';DROP TABLE FOO;--' It would not drop any table, but search the customertable for the customername ';DROP TABLE FOO;-- which, I suppose, won't be found ;-) Now after a while of writing statements and protecting myself against SQL-Injection with this method, I read that many developers use parameterized statements, but I never read an article where "our" method was used. So definitely there is a good reason for it. What scenarios would parameterized statements cover but our method doesn't? What are the advantages of parameterized statements compared to our method? Thanks Philipp

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How do I write this as an expression?

- by itchi

I'm trying to rewrite a linq to entities query to an expression. My model is a School can have many Persons where Persons are inherited out to teachers, students, etc. The following query works for me: IQueryable<DAL.TEACHER> teacher = from p in School select p.PERSON as ESBDAL.TEACHER; How would I write this as a query expression? I thought something like: IQueryable<DAL.TEACHER> teacher = School.Select(x=>x.PERSON) as IQueryable<DAL.TEACHER>; ...but it does not. Am I misunderstanding the .Select()?

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varchar comparison in SQL Server

- by Ram

I am looking for some SQL varchar comparison function like C# string.compare (we can ignore case for now, should return zero when the character expression are same and a non zero expression when they are different) Basically I have some alphanumeric column in one table which needs to be verified in another table. I cannot do select A.col1 - B.col1 from (query) as "-" operator cannot be applied on character expressions I cannot cast my expression as int (and then do a difference/subtraction) as it fails select cast ('ASXT000R' as int) Conversion failed when converting varchar 'ASXT000R' to int Soundex would not do it as soundex is same for 2 similar strings Difference would not do it as select difference('abc','ABC') = 4 (as per msdn, difference is the difference in the soundex of 2 character expressions and difference =4 implies least different) Is there any other way of doing it ?

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pass form builder in remote_function in rails ?

- by richard moss

hi all i have select box where on change i need to grab the value and via remote function get some field names from db and then generate those field further down the form depwning on whatoption from the select box is chosen. The problem is is that the fields are in a f.form_for so are using the formbuilder f that has the select box in. So when i render the partial via ajax in the controller i get an error as i dont have a reference to the local form builder f. does anyone know how or if i can get reference to the form builder orif can pass it in a remote function call and then pass into my locals in the partial ? thanks alot, any help will be great as been stuck on this a long time! cheers rick

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Where clause in joins vs Where clause in Sub Query

- by Kanavi

DDL create table t ( id int Identity(1,1), nam varchar(100) ) create table t1 ( id int Identity(1,1), nam varchar(100) ) DML Insert into t( nam)values( 'a') Insert into t( nam)values( 'b') Insert into t( nam)values( 'c') Insert into t( nam)values( 'd') Insert into t( nam)values( 'e') Insert into t( nam)values( 'f') Insert into t1( nam)values( 'aa') Insert into t1( nam)values( 'bb') Insert into t1( nam)values( 'cc') Insert into t1( nam)values( 'dd') Insert into t1( nam)values( 'ee') Insert into t1( nam)values( 'ff') Query - 1 Select t.*, t1.* From t t Inner join t1 t1 on t.id = t1.id Where t.id = 1 Query 1 SQL profiler Result Reads = 56, Duration = 4 Query - 2 Select T1.*, K.* from ( Select id, nam from t Where id = 1 )K Inner Join t1 T1 on T1.id = K.id Query 2 SQL Profiler Results Reads = 262 and Duration = 2 You can also see my SQlFiddle Query - Which query should be used and why?

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swf file upload control not filtering the files for the second time

- by subash

iam using swf file upload control in my application developed in asp.net & c#.net. i am having a dropdown box with file types like jpeg,.xls ,.txt etc. so when i select particular file type in the dropdown and clicking on the button would open a filedialog showing only the files of the type selected in the dropdown. The problem is that when i select "jpeg" for the first time file dialog shows only jpeg files. when i select ".xls" next time it shows again the prevoiusly selected jpeg files and not currently selected ".xls". but while debugging it was found the file type definition in the swf code has been changed to .xls . can any one guide why the file upload control not mapping the selected file for the second time

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In SQL / MySQL, can a Left Outer Join be used to find out the duplicates when there is no Primary ID

- by Jian Lin

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Search found 29816 results on 1193 pages for 'select tag'.

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- by Anthony Potts

- by Adiasz

- by shantanuo

- by vamsivanka

- by andufo

- by Gublooo

- by user1734651

- by askkirati

- by Newbie

- by Omnipresent

- by armandino

- by Andrew

- by alex

- by Roland Bengtsson

- by Kiril

- by Larry

- by Laurence

- by Nickson

- by Philipp G

- by itchi

- by Ram

- by richard moss

- by Kanavi

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