Tagged Questions

An acronym for "Structured Query Language" (it's not the name of a specific DBMS product), SQL can be used in relational database management systems (RDBMS) to query, update, delete, and insert data as well as modify the structure of the database. It can also be used to manage schemas and data ...

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1answer
70 views

Query performance issues

I need help in improving the performance of the following query. It has the purpose to select one record out of a group of records with an identical ID (doublettes). Rules are that Date2 must be the ...
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0answers
11 views

first query on my table takes apx: 0 sec but taking too much time on or after 3 to 4 query

I have the following table in mysql database: CREATE TABLE `chronologicallists` ( `sno` int(250) NOT NULL AUTO_INCREMENT, `empSno` int(11) NOT NULL COMMENT 'Employee Serial Number', ...
0
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1answer
22 views

update column without auto timestamp update

Hello everyone I have got a product stock table with a time-stamp column so the so any updated to that row will update the time stamp ,I'm happy with this setting but sometimes I want to update the ...
0
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1answer
39 views

Index file - size changed

I realised today that my index file(which is about 250GB) is smaller than yesterday for about 7GB. Everything, I done in the meantime, was index rebuild. Is it possible that index rebuild is the ...
0
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1answer
23 views

numbering distinct column values in an ordering but not just displaying the total

I have a column with non-unique entries, we'll call this column "State" (representing the state where an order was shipped to) and a second column called "Times" (representing the times that an order ...
0
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1answer
20 views

How to get all the months from the last paid date in MySql?

I need to get the all the months from the last_payment_Date for the user from that table for processing purposing. As of now i am using this query.. SELECT `Name`, `Acc_No` FROM `user_table_details` ...
0
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1answer
23 views

How to model efficient permission checks for a social network?

The goal is to build a facebook like permission system. So that users can grant other users access on objects based on a direct assignment (allow user X to see posts) or allow users to access them ...
1
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1answer
32 views

How to Choose an SQL Database for Simple Data Preparation & Analytics

In the interests of not making this a shopping list: please advise on "how" to choose a the right tool, as opposed to which is the best. E.g: Which questions should I be asking myself / client? What ...
0
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1answer
30 views

Query to select distinct name based on several factors

I have a table with the following data (simplified here): ID | PolicyName | Setting | State | Value 1 Default DiskUsage Enabled 1 2 Default Memory Enabled 1 3 Default CPU Enabled 0 4 Personal ...
0
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1answer
69 views

Delete and merge duplicate records from joined tables?

I am trying to delete duplicate records from the output of the query below. If they also meet certain conditions i.e., 'different address type', then I would merge the records. From the following ...
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0answers
11 views

Are there any minimal sqlite extensions for running a server with role based access control? [closed]

I need to run an SQL server with role/user based access control in a very resource limited environment. Are there any extensions or open source projects for sqlite to provide this functionality? ...
0
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1answer
48 views

Doing a insert across two databases with same collations and getting an error

SQL query : insert DB1.dbo.tbl1 select distinct Number, Name, 'Unknown', 'Unknown', 'Unknown', NULL, 'No', 'GL', 'N/A' from DB2.dbo.tbl1 T2 where T1.Number not in (select distinct AccountNumber ...
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1answer
104 views

Stored procedure takes 18 seconds on first load, 0 seconds on subsequent loads, waiting several minutes makes it slow again

I have a stored procedure that returns a lot of data for a business dashboard. On first load it takes 18 seconds, after that it takes 0 seconds, even if I change the input parameters at random it ...
0
votes
2answers
51 views

SQL Server database performance is very poor after a month of use [closed]

I am quite new to SQL server and have a question regarding database speed. The database (about 50 MB big) was very fast in the beginning. Now, a month later, the speed is a lot worse. I run a script ...
0
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5answers
83 views

Database with only text fields

I started working on an existing SQL Server Database System in which most of the fields are stored as text. Except some IDs all fields are varchar (phone numbers, zip codes, Dates, addresses, monetary ...
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3answers
42 views

how to order a field based on two parts of the row value

I have a field with contents of the form 22/4, 30/8, 30/5, 30/3 I want it ordered in the form 22/4, 30/3, 30/5, 30/8 with the part after / ordered if the part before / is same! Please help!!
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2answers
45 views

Is there anyway to search PL/SQL reserved words with contains function?

Is there anyway to search PL/SQL reserved words with the contains function in the Oracle? We would like to search keywords such as "test for" or "test do" with the contains or catsearch functions ...
5
votes
2answers
199 views

Strange query results for DELETE with ROW_NUMBER

In the following DELETE statement I try to delete all rows except the first one ordered by some criteria. (The actual query makes more sense, this is just a repro. All the sys.objects stuff is just ...
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votes
1answer
37 views

Subqueries in SQL Server 2014 [closed]

I want to get results that is in more than one row using a subquery. here is what: Note. This is in microsoft SQL Server 2014. Relations: FeeStudent(Feeid, Studentid, MODE,LEVEL, SEM, Paid, Status) ...
2
votes
1answer
29 views

Best way of finding rows referencing a given id on PostgreSQL

I'm trying to find if there would be anything violating the foreign key constraint when deleting a row, to check if I can delete it or not (can't use ON DELETE CASCADE) For that, I have a piece of ...
1
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2answers
70 views

Fourth inner join to the same table increases query duration significantly

As soon as I add a fourth inner join to a specific table, the query duration increases significantly: sub 1sec to 45sec. The table in question is deployments d4. The SQL Query: select a.id as ...
1
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3answers
54 views

Performance first low, then high after adding index, then keep high after drop index

I am testing performance a complicated select query. It is very slow. using explain, I have found a ALL in type COLUMN. Then I ADD INDEX. result comes out fast. However, when I DROP the INDEX I ...
2
votes
2answers
54 views

Oracle: Helping hand writing this query. Do I need a sub query here?

I have the below query that returns the number of orders created on a particular customer number per month for the past 2 years. SQL SELECT TO_CHAR(o.entry_date, 'MM'), SUM(CASE ...
1
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1answer
26 views

group records according to column

hi how can make this result query: to this: I have this code and i know it's still farfetched: select max(case subcod when 'DISABILITY' then A end) as disability, max(case ...
2
votes
2answers
197 views

Join 3 tables and return only distinct values for max datetime

I've been trying to do this the whole 2 weeks but seems like to no avail. 3 tables involved here. but am expecting the result would be distinct case no. for the same date & user. otherwise, it ...
0
votes
1answer
55 views

SQL Server 2008 and constant expressions

If I have the following scenario, would Replace be evaluated a single time? DECLARE @text nvarchar(32) = 'This is a test field' SELECT textField FROM Table WHERE Id = @idICareAbout AND textField = ...
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0answers
25 views

Receiving duplicate results in one condition of JOINED query

I always end up here when Googling for solutions, so I thought I'd cut out the middleman since I'm unable to fix this via searching/forums. It's my first time posting, so please forgive any faux pas ...
2
votes
0answers
69 views

SSRS URL Changes while navigating

I am trying to track down the root cause of this issue I keep seeing. We have SSRS running with a custom URL like https://reporting.companyname.com/reports. When I connect to that address I can ...
3
votes
1answer
99 views

Need help with a Running Total Issue

Using SQL-Server 2008 R2 and Report Builder 3.0 Here is my query without the running total column: SELECT CostManagement_CommitmentDetails.Id ,CostManagement_CommitmentDetails.LineNumber AS ...
1
vote
1answer
46 views

2 Date Ranges - How many days from one range excluding weekends overlap

First - Thanks for your help. I'm looking to create a query in SQL that provides the me the # of days from one date range that overlap another date range and excludes weekends. Example Data: ...
0
votes
1answer
30 views

MySQL: Rank by Department in an employees table

I need Mysql query to rank the hours used by each department in an employees table, but it just ranks all without taking into consideration the departments.
1
vote
1answer
35 views

How to query a list of all the different errors?

I have a DB which is very big and stores a lot of eventlogs, around 15 million rows. When I try this query, it is totally impossible to get some results. Any idea how I could do this? Maybe indexed ...
1
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3answers
32 views

Study material for Advanced Databases module inc SQL, Relational Model, ERM & TM [closed]

For my next module in my masters, I am planning on studying Advanced Databases. (Long story short, the masters is designed for people with NON-CS degrees, so I have never studied databases, therefore ...
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1answer
35 views

Oracle Concurrent Insertion

We have simple case like Create table t1 (c1 number primary); session1: insert into t1 values (1); //session1 do not commit transaction session2: insert into t1 values (2); Will Session2 ...
2
votes
2answers
40 views

SQL Insert Statement Persists Two Records When I Need Just One

I have altered it to include hardcoded variables when I pulled this chunk of code from the stored procedure. I ran it independent of the application with the same result. I need one insert statement ...
0
votes
1answer
19 views

SQL Insert Statement Persists Two Records When I Need Just One [duplicate]

I have altered it to include hardcoded variables when I pulled this chunk of code from the stored procedure. I ran it independent of the application with the same result. I need one insert statement ...
2
votes
2answers
61 views

Using collate: When to use and when not to use

In one of my applications we had tsql like shown below SELECT DISTINCT [Dblist].[DbName] AS [DbName] FROM [Common].dbo.[Dblist] WHERE dbname not in ( SELECT [name] FROM ...
2
votes
0answers
21 views

Best way to get time zone key name from SQL Server

Below is what I pieced together but I wanted to see what other ways are available. SET NOCOUNT ON; GO DECLARE @tz VARCHAR(50) EXEC [master].[dbo].[xp_regread] 'HKEY_LOCAL_MACHINE' ...
0
votes
1answer
34 views

to pivot or not to pivot - schema design question [closed]

I am implementing something similar to this schema http://www.databaseanswers.org/data_models/event_reservations/index.htm It occurs to me that the pivot table for Customer_Bookings would just keep ...
2
votes
3answers
231 views

Run multiple stored procedures in sequence

I have a stored procedure written in T-SQL (SQL Server 2008 R2). It is a master procedure that essentially call multiple other subprocedures in sequence. The call and error handling is identical for ...
0
votes
2answers
43 views

Merging tables, but ignoring duplicate columns

I have two tables I want to merge: city1(id, city, state, zip, lat, lon, county) city2(id, city, state) The tables contain overlapping city and state, but not primary keys. I can't figure out how ...
0
votes
3answers
37 views

Converting huge ASCII file to flat and convert

I am not a db administrator but I thought to ask this question here. I have several very large ASCII files (3-5GB each) that I need to extract the data and then sort it. The instructions say to ...
0
votes
4answers
64 views

SQL Server combine Update and Delete

Is it possible to combine both update and delete in a single SQL statement? I would like to execute something like this: update a set a.value = a.value + b.value from Table1 a join Table2 b on a.ID = ...
1
vote
2answers
38 views

MS SQL Server 2012 Log Shipping Questions

I have a few questions regarding Log Shipping in SQL Server 2012. 1) If the primary database server dies, is it possible to allow users to connect to the secondary database so as to continue working ...
1
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0answers
14 views

Is there a faster way to get UNION ALL behavior in Postgres? [duplicate]

I have a table (t0), in my Postgres DB, with data that looks something like this: t1_id t2_id 1 1 2 1 2 1 4 null 4 null 5 null And I have a query to return my ...
1
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0answers
21 views

Multidimensional aggregates

Suppose one wanted to cache simple aggregate data over a table or grouped parts of a table, one could simply make a table with the aggregated results. If the original table is only appended to, it is ...
0
votes
2answers
21 views

Create a test enviroment in Oracle 10g

I have a production enviroment in a Oracle 10g database which I would like to authomatically duplicate in a test enviroment. My production enviroment is just a number of tables in which I have usually ...
0
votes
1answer
33 views

Query output conditional upon values in dataset

If the number column contains values 5 AND 6, AND the value X exists in the chr column, I would like to exclude rows with 10 in the test column. But, if the number column contains values 4 AND 5, AND ...
2
votes
1answer
72 views

PostgreSQL return second 'Group' as an array

I have some tables that include websites and visitors and I am trying to write a query that produces a 'top 10' for each site, the tables look something like this... websites ------- website_id (pk) ...
5
votes
2answers
72 views

Is the runtime of checking for duplicate primary keys in SQL Server O(n)?

I was curious and I couldn't find too much info on this. Is it also O(n) for checking for duplicates among primary keys? Is it the same for most other SQL databases? Is there a place that lists this ...