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  • count(*) vs count(row-name) - which is more correct?

    - by bread
    Does it make a difference if you do count(*) vs count(row-name) as in these two examples? I have a tendency to always write count(*) because it seems to fit better in my mind with the notion of it being an aggregate function, if that makes sense. But I'm not sure if it's technically best as I tend to see example code written without the * more often than not. count(*): select customerid, count(*), sum(price) from items_ordered group by customerid having count(*) > 1; vs. count(row-name): SELECT customerid, count(customerid), sum(price) FROM items_ordered GROUP BY customerid HAVING count(customerid) > 1;

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  • Return multiple IDs from a function and use the result in a query

    - by NewK
    I have this function that returns me all children of a tree node: CREATE OR REPLACE FUNCTION fn_category_get_childs_v2(id_pai integer) RETURNS integer[] AS $BODY$ DECLARE ids_filhos integer array; BEGIN SELECT array ( SELECT category_id FROM category WHERE category_id IN ( (WITH RECURSIVE parent AS ( SELECT category_id , parent_id from category WHERE category_id = id_pai UNION ALL SELECT t.category_id , t.parent_id FROM parent INNER JOIN category t ON parent.category_id = t.parent_id ) SELECT category_id FROM parent WHERE category_id <> id_pai ) ) ) into ids_filhos; return ids_filhos; END; and I would like to use it in a select statement like this: select * from teste1_elements where category_id in (select * from fn_category_get_childs_v2(12)) I've also tried this way with the same result: select * from teste1_elements where category_id=any(select * from fn_category_get_childs_v2(12))) But I get the following error: ERROR: operator does not exist: integer = integer[] LINE 1: select * from teste1_elements where category_id in (select *... ^ HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts. The function returns an integer array, is that the problem? SELECT * from fn_category_get_childs_v2(12) retrieves the following array (integer[]): '{30,32,34,20,19,18,17,16,15,14}'

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  • What does P mean in Sort(Expression<Func<T, P>> expr, ListSortDirection direction)?

    - by Grasshopper
    I am attempting to use the answer in post: How do you sort an EntitySet<T> to expose an interface so that I can sort an EntitySet with a Binding list. I have created the class below and I get the following compiler error: "The type or namespace 'P' could not be found (are you missing a using directive or assembly reference?). Can someone tell me what the P means and which namespace I need to include to get the method below to compile? I am very new to delegates and lamba expressions. Also, can someone confirm that if I create a BindingList from my EntitySet that any modifications I make to the BindingList will be made to the EntitySet? Basically, I have an EntitySet that I need to sort and make changes to. Then, I will need to persist these changes using the original Entity that the BindingList came from. public class EntitySetBindingWrapper<T> : BindingList<T> { public EntitySetBindingWrapper(BindingList<T> root) : base(root) { } public void Sort(Expression<Func<T, P>> expr, ListSortDirection direction) { if (expr == null) base.RemoveSortCore(); MemberExpression propExpr = expr as MemberExpression; if (propExpr == null) throw new ArgumentException("You must provide a property", "expr"); PropertyDescriptorCollection descriptorCol = TypeDescriptor.GetProperties(typeof(T)); IEnumerable<PropertyDescriptor> descriptors = descriptorCol.Cast<PropertyDescriptor>(); PropertyDescriptor descriptor = descriptors.First(pd => pd.Name == propExpr.Member.Name); base.ApplySortCore(descriptor, direction); } }

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  • asp:QueryStringParameter and empty query string parameter

    - by abatishchev
    I haveasp:GridView displaying client requests using asp:SqlDataSource. I want to limit displayed information by client: View.aspx has to display everything, View.aspx?client=1 has to display only requests from client ID #1. So I'm using <asp:QueryStringParameter Name="client" QueryStringField="client" /> for query "EXEC getRequests @client". Everything works properly when some client is specified. But don't - if not. I tested my SP using SSMS - it works properly in both cases - when parameter is specified and when it isn't (NULL passed explicitly). What have I do?

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  • connecting to mysql from excel: ODBC driver does not support the requested properties.

    - by every_answer_gets_a_point
    i am trying to add data to mysql from excel. i am getting the above error on this line: rs.Open strSQL, oConn, adOpenDynamic, adLockOptimistic here is my code: Dim oConn As ADODB.Connection Private Sub ConnectDB() Set oConn = New ADODB.Connection oConn.Open "DRIVER={MySQL ODBC 5.1 Driver};" & _ "SERVER=localhost;" & _ "DATABASE=employees;" & _ "USER=root;" & _ "PASSWORD=some_pass;" & _ "Option=3" End Sub Function esc(txt As String) esc = Trim(Replace(txt, "'", "\'")) End Function Private Sub InsertData() Dim rs As ADODB.Recordset Set rs = New ADODB.Recordset ConnectDB With wsBooks For rowCursor = 2 To 11 strSQL = "INSERT INTO tutorial (author, title, price) " & _ "VALUES ('" & esc(.Cells(rowCursor, 1)) & "', " & _ "'" & esc(.Cells(rowCursor, 2)) & "', " & _ esc(.Cells(rowCursor, 3)) & ")" rs.Open strSQL, oConn, adOpenDynamic, adLockOptimistic Next End With End Sub whats wrong with rs.Open strSQL, oConn, adOpenDynamic, adLockOptimistic ? why am i getting the odbc error?

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  • Query to find duplicate item in 2 table

    - by Rico
    I have this table Antecedent Consequent I1 I2 I1 I1,I2,I3 I1 I4,I1,I3,I4 I1,I2 I1 I1,I2 I1,I4 I1,I2 I1,I3 I1,I4 I3,I2 I1,I2,I3 I1,I4 I1,I3,I4 I4 AS you can see it's pretty messed up. is there anyway i can remove rows if item in consequent exist in antecedent (in 1 row) for example: INPUT: Antecedent Consequent I1 I2 I1 I1,I2,I3 <---- DELETE since I1 exist in antecedent I1 I4,I1,I3,I4 <---- DELETE since I1 exist in antecedent I1,I2 I1 <---- DELETE since I1 exist in antecedent I1,I2 I1,I4 <---- DELETE since I1 exist in antecedent I1,I2 I1,I3 <---- DELETE since I1 exist in antecedent I1,I4 I3,I2 I1,I2,I3 I1,I4 <---- DELETE since I1 exist in antecedent I1,I3,I4 I4 <---- DELETE since I4 exist in antecedent OUTPUT: Antecedent Consequent I1 I2 I1,I4 I3,I2 is there anyway i can do that by query?

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  • Subquery with multiple results combined into a single field?

    - by Todd
    Assume I have these tables, from which i need to display search results in a browser: Table: Containers id | name 1 Big Box 2 Grocery Bag 3 Envelope 4 Zip Lock Table: Sale id | date | containerid 1 20100101 1 2 20100102 2 3 20091201 3 4 20091115 4 Table: Items id | name | saleid 1 Barbie Doll 1 2 Coin 3 3 Pop-Top 4 4 Barbie Doll 2 5 Coin 4 I need output that looks like this: itemid itemname saleids saledates containerids containertypes 1 Barbie Doll 1,2 20100101,20100102 1,2 Big Box, Grocery Bag 2 Coin 3,4 20091201,20091115 3,4 Envelope, Zip Lock 3 Pop-Top 4 20091115 4 Zip Lock The important part is that each item type only gets one record/row in the return on the screen. I accomplished this in the past by returning multiple rows of the same item and using a scripting language to limit the output. However, this makes the ui overly complicated and loopy. So, I'm hoping I can get the database to spit out only as many records as there are rows to display. This example may be a bit extreme because of the 2 joins needed to get to the container from the item (through the sale table). I'd be happy for just an example query that outputs this: itemid itemname saleids saledates 1 Barbie Doll 1,2 20100101,20100102 2 Coin 3,4 20091201,20091115 3 Pop-Top 4 20091115 I can only return a single result in a subquery, so I'm not sure how to do this.

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  • How to write contents of a rails database to external file

    - by user1296787
    I'm trying to have rails send the contents of my database to an external textfile. I wanted this done everytime a new user is created. However, when i try to do the following in my user.rb model file, before_save :write_data def write_data() File.open("data.txt", "w") do |myfile| myfile.write(User.all) end end It doesn't write the actual contents of the database, instead, it displays something like this User:0x109858540 Can anyone help? Thanks.

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  • How efficient is a details table?

    - by Jeffrey Lott
    At my job, we have pseudo-standard of creating one table to hold the "standard" information for an entity, and a second table, named like 'TableNameDetails', which holds optional data elements. On average, for every row in the main table will have about 8-10 detail rows in it. My question is: What kind of performance impacts does this have over adding these details as additional nullable columns on the main table?

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  • possible way to attach database to exe

    - by ali
    i created a small application using c# winforms that uses mssql as a database. is there a way to attach the database to the exe file so i won't need to install sqlserver on all the machines that i want to run the program on?

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  • MySQL Query to find consecutive available times of variable lenth

    - by Armaconn
    I have an events table that has user_id, date ('2013-10-01'), time ('04:15:00'), and status_id; What I am looking to find is a solution similar to http://stackoverflow.com/questions/2665574/find-consecutive-rows-calculate-duration but I need I need two additional components: 1) Take date into consideration, so 10/1/2013 at 11:00 PM - 10/2/2013 at 3:00AM. Feel free to just put in a fake date range (like '2013-10-01' to '2013-10-31') 2) Limit output to only include when there are 4+ consecutive times (each event is 15 minutes and I want it to display minimum blocks of an hour, but would also like to be able to switch this restriction to 1.5 hours or some other duration if possible). SUMMARY - Looking for a query that provides the start and end times for a set of events that have the same user_id, status_id, and are in a continuous series based on date and time. For which I can restrict results based on date range and minimum series duration. So the output should have: user_id, date_start, time_start, date_end, time_end, status_id, duration CREATE TABLE `events` ( `event_id` int(11) NOT NULL auto_increment COMMENT 'ID', `user_id` int(11) NOT NULL, `date` date NOT NULL, `time` time NOT NULL, `status_id` int(11) default NULL, PRIMARY KEY (`event_id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1568 ; INSERT INTO `events` VALUES(1, 101, '2013-08-14', '23:00:00', 2); INSERT INTO `events` VALUES(2, 101, '2013-08-14', '23:15:00', 2); INSERT INTO `events` VALUES(3, 101, '2013-08-14', '23:30:00', 2); INSERT INTO `events` VALUES(4, 101, '2013-08-14', '23:45:00', 2); INSERT INTO `events` VALUES(5, 101, '2013-08-15', '00:00:00', 2); INSERT INTO `events` VALUES(6, 101, '2013-08-15', '00:15:00', 1); INSERT INTO `events` VALUES(7, 500, '2013-08-14', '23:45:00', 1); INSERT INTO `events` VALUES(8, 500, '2013-08-15', '00:00:00', 1); INSERT INTO `events` VALUES(9, 500, '2013-08-15', '00:15:00', 2); INSERT INTO `events` VALUES(10, 500, '2013-08-15', '00:30:00', 2); INSERT INTO `events` VALUES(11, 500, '2013-08-15', '00:45:00', 1); Desired output row |user_id | date_start | time_start | date_end | time_end | status_id | duration 1 |101 |'2013-08-14'| '23:00:00' |'2013-08-15'|'00:15:00'| 2 | 5 2 |101 |'2013-08-15'| '00:00:15' |'2013-08-15'|'00:30:00'| 1 | 1 3 |500 |'2013-08-14'| '00:23:45' |'2013-08-15'|'00:15:00'| 1 | 2 4 |500 |'2013-08-15'| '00:00:15' |'2013-08-15'|'00:45:00'| 2 | 2 5 |500 |'2013-08-15'| '00:00:45' |'2013-08-15'|'01:00:00'| 2 | 1 *except that rows 2 and 5 wouldn't appear if duration had to be greater than 30 minutes Thanks for any help that you can provide! And please let me know if there is anything I can further clarify!!

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  • Can a primary key be equal to a different column?

    - by eric
    I know that a primary key must be unique, but is it okay for a primary key to be equal to a different column in the same table by coincidence? For instance, I have 2 tables. One table is called person that holds information about a person (ID, email, telephone, address, name). The other table is staff (ID, pID(person ID), salary, position). In staff the ID column is the primary key and is used to uniquely identify a staff member. The number is from 1 - 100. However, the pID (person ID) may be equal to the ID. For instance the staff ID may be 1 and the pID that it references to may be equal to 1. Is that okay?

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  • How would I associate a "Note" class to 4+ classes without creating lookup table for each associatio

    - by Gthompson83
    Im creating a project tasklist application. I have project, section, task, issue classes, and would like to use one class to be able to add simple notes to any object instance of those classes. The task, issue tables both use a standard identity field as a primary key. The section table has a two field primary key. The project table has a single int primary key defined by the user. Is there a way to associate the note class with each of these without using a seperate lookup table for each class? I'm not so sure my original idea is a decent way to implement this. I considered the following (each variable mapping to a field n the notes table. Private _NoteId As Integer Private _ProjectId As Integer Private _SectionId As Integer Private _SectionId2 As Integer Private _TaskId As Integer Private _IssueId As Integer Private _Note As String Private _UserId As Guid Then I would be able to write seperate methods (getProjectNotes, getTaskNotes) to get notes attached to each class. I started writing this a few weeks ago but got pulled away before i could finish. When revisiting this code today my first thought "this is retarded". Thoughts on drawbacks to this design?

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  • Access is refusing to run an query with linked table?

    - by Mahmoud
    Hey all i have 3 tables each as follow cash_credit Bank_Name-------in_date-------Com_Id---Amount America Bank 15/05/2010 1 200 HSBC 17/05/2010 3 500 Cheque_credit Bank_Name-----Cheque_Number-----in_date-------Com_Id---Amount America Bank 74835435-5435 15/05/2010 2 600 HSBC 41415454-2851 17/05/2010 5 100 Companies com_id----Com_Name 1 Ebay 2 Google 3 Facebook 4 Amazon Companies table is a linked table when i tried to create an query as follow SELECT cash_credit.Amount, Companies.Com_Name, cheque_credit.Amount FROM cheque_credit INNER JOIN (cash_credit INNER JOIN Companies ON cash_credit.com_id = Companies.com_id) ON cheque_credit.com_id = Companies.com_id; I get an error saying that my inner Join is incorrectly, this query was created using Access 2007 query design the error is Type mismatch in expression then i thought it might be the inner join so i tried Left Join and i get an error that this method is not used JOIN expression is not supported I am confused on where is the problem that is causing all this

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  • Index for wildcard match of end of string

    - by Anders Abel
    I have a table of phone numbers, storing the phone number as varchar(20). I have a requirement to implement searching of both entire numbers, but also on only the last part of the number, so a typical query will be: SELECT * FROM PhoneNumbers WHERE Number LIKE '%1234' How can I put an index on the Number column to make those searchs efficient? Is there a way to create an index that sorts the records on the reversed string? Another option might be to reverse the numbers before storing them, which will give queries like: SELECT * FROM PhoneNumbers WHERE ReverseNumber LIKE '4321%' However that will require all users of the database to always reverse the string. It might be solved by storing both the normal and reversed number and having the reversed number being updated by a trigger on insert/update. But that kind of solution is not very elegant. Any other suggestions?

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  • Oracle 10g multiple DELETE statements

    - by bmw0128
    I'm building a dml file that first deletes records that may be in the table, then inserts records. Example: DELETE from foo where field1='bar'; DELETE from foo where fields1='bazz'; INSERT ALL INTO foo(field1, field2) values ('bar', 'x') INTO foo(field1, field2) values ('bazz', 'y') SELECT * from DUAL; When I run the insert statement by itself, it runs fine. When I run the deletes, only the last delete runs. Also, it seems to be necessary to end the multiple insert with the select, is that so? If so, why is that necessary? In the past, when using MySQL, I could just list multiple delete and insert statements, all individually ending with a semicolon, and it would run fine.

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  • move data from one table to another, postgresql edition

    - by IggShaman
    Hi All, I'd like to move some data from one table to another (with a possibly different schema). Straightforward solution that comes into mind is - start a transaction with serializable isolation level; INSERT INTO dest_table SELECT data FROM orig_table,other-tables WHERE <condition>; DELETE FROM orig_table USING other-tables WHERE <condition>; COMMIT; Now what if the amount of data is rather big, and the <condition> is expensive to compute? In PostgreSQL, a RULE or a stored procedure can be used to delete data on the fly, evaluating condition only once. Which solution is better? Are there other options?

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  • postgres subquery w/ derived column

    - by Wells
    The following query won't work, but it should be clear what I'm trying to do: split the value of 't' on space and use the last element in that array in the subquery (as it will match tl). Any ideas how to do this? Thanks! SELECT t, y, "type", regexp_split_to_array(t, ' ') as t_array, sum(dr), ( select uz from f.tfa where tl = t_array[-1] ) as uz, sc FROM padres.yd_fld WHERE y = 2010 AND pos <> 0 GROUP BY t, y, "type", sc;

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  • Should I sanitize EVERY form variable passed along?

    - by Camran
    I have a form with many fields... The action is set to a php page which queries mysql... Should I sanitize with mysql_real_escape_string every single variable? Or can I ignore sanitizing drop-lists and radios for instance? Also, besides mysql_real_escape_string, what else should I do to prevent attacks? Thanks

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  • sequence of events in ACCESS

    - by I__
    what is the proper way of doing the following: getting DATE as user input running a query generating a report that uses the query this is the solution i was thinking: have a form that takes user input run the query open the report what is the correct way of doing this?

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