Structured Query Language (SQL). For questions about the language, not Microsoft SQL Server (tag sql-server).

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How to delete large amount of data from a sql table?

We ran out of disk space and we have a table with about 10million records. We'd like to delete the old records which are about 2million. What are the impact of just deleting these using a simple ...
4
votes
1answer
725 views

Why does WAITFOR (RECEIVE FROM QUEUE) show up in the monitor incorrectly?

I kick off the following command in my app: WAITFOR (RECEIVE CONVERT(int, message_body) AS Message FROM MyQueue) When I run `sp_who2 active', I get Status=SUSPENDED and Command=DELETE Note: ...
13
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2answers
516 views

Does firing off an indefinite WAITFOR increase the log file size?

In the last release of my app, I added a command that tells it to wait when something arrives in the Service Broker queue: WAITFOR (RECEIVE CONVERT(int, message_body) AS Message FROM MyQueue) The ...
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2answers
508 views

Oracle SQL Query/SubQuery Single column with mutilple data [closed]

Id File-Name Descrption 1 yyyy Started 2 yyyy incompleted 3 rrrr Started 4 tttt started 5 uuuu started 6 rrrr completed 7 tttt completed 8 uuuu ...
3
votes
1answer
579 views

How to categorize rows by SUM of a column in mysql?

I have a table as id num_items folder 1 4 2 33 3 74 4 41 5 24 6 34 7 46 8 55 9 11 I want to assign folder number to rows but limiting the number of items in each folder (e.g. ...
1
vote
1answer
299 views

MapReduce performance on a single PC [closed]

I have heard that Hadoop has better performance than MySQL. Until now, I have used relational databases so this is really new technology for me. I have a 6 core PC. Suppose I have a table with 20 ...
1
vote
0answers
378 views

big mysql database optimization

My Joomla mysql database has about 3.4 million rows in content table. It is just static article. Very slow and often use out of resources. To speed up it, I segmented it into 6 sub-tables and added ...
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2answers
558 views

Automatic create SQL database and table relationship

For SQL Server 2008, what is the best way to automatically "draw up" the Database relation ship and table relationship too? Is there any way to visualize database with this.
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2answers
856 views

Combining two similar SQL queries

I'm using the following SQL query twice with different values of limit. In my case, 40 and 100, though it doesn't really matter. My question is - can I combine these two queries into one query? It ...
0
votes
1answer
4k views

How to UPDATE a column to SET previous row value to NULL cells?

I have a table as id value 1 music 2 3 movie 4 5 6 book 7 8 Some values are missing, and I want to assign the value of previous row to produce id value 1 music 2 music 3 movie 4 ...
1
vote
1answer
124 views

How to aggregate datapoints in a table?

Suppose I have following table - CREATE TABLE data_points (t DATETIME PRIMARY KEY, value INTEGER); I want to aggregate the data by calculating average of every 10 points in the table. i.e. If ...
0
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1answer
139 views

clustered index - data warehouse

My source data comes from multiple OLTP databases where the primary key is an identitiy column. We anticipate adding data centers and/or splitting the databases by product. Currently i have one system ...
3
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1answer
1k views

Profiler TextData output is null

I am doing a trace on a database and dumping the trace realtime into a table. The reason I'm doing a trace is I want to see all the queries that are being executed against the database. +-----------+...
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votes
2answers
1k views

How to GROUP_CONCAT between given rows?

I have a table as id diary 1 breakfast 2 walk 3 start 4 office works 5 office projects 6 end 7 taxi 8 start 9 preparing for meeting 10 doing the meeting 11 end 12 night I want ...
2
votes
1answer
317 views

avoid insert xml duplicate data

how can to prevent duplicate inserts for every Execute? insert into IQ (XMLDT)values('<row>sdsdf</row>')
6
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1answer
1k views

ANSI/ISO plans for LIMIT standardization?

Are there currently plans to standardize one best way of limiting the number of results returned by a query? The stack overflow question at Is there an ANSI SQL alternative to the MYSQL LIMIT ...
1
vote
1answer
1k views

Splitting a column to normalized table

I have a de-normalized table as Original De-Normalized Table id text 23 first,second|third,fourth,fifth|sixth I want to normalize the database to create the following tables Table 1: (Split by "...
6
votes
2answers
16k views

How to Drop Database in Single_User Mode

How do I drop a database which shows DatabaseName (Single User) as its name? When I try to delete it, I get the following error: Alter failed for Database 'DatabaseName'. (Microsoft.SqlServer....
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2answers
588 views

Merging multiple databases as separate schemas in PostgreSQL

I have to combine data from 4 different databases. Each having its own design. What i want to do is to Create a new database with my desired schema. and one schema per (to be merged) database Then ...
1
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3answers
705 views

Which RDBMS has the most advanced “table-valued” functions?

Every Database Management System focuses on specific features and applications. I am using mysql, probably as it is popular and satisfies common needs. However, I came across a problem, which needs ...
2
votes
2answers
835 views

Reordering data in a table

I have a table that stores sensor data (in SQLite) and looks like this; TABLE Timestream: idTimestream PK autoincrementing integer, time int not null, value float not null, idSensor integer not ...
3
votes
2answers
1k views

How to split a string to and get info from another table in mysql

I have a system to assign score for each sentence stored in a column: TABLE 1: word_scores word score this 3 is 4 a 5 test 1 another 0 sentence 8 TABLE 2: ...
0
votes
2answers
214 views

How can I optimize this query and support multiple SKUs?

My current query only can select one SKU at a time. I can leave salesite_id constant. If there is a way to also have varying salesite_ids that would be good too, but not necessary. Also any ...
4
votes
2answers
3k views

How do you set the pagesize, codeset and table space when creating a database in DB2?

I want to create a database in DB2. I found some information on this page I want to use only some options which are explained on the page: PAGESIZE CODESET TABLESPACE Then, I want to add/...
0
votes
1answer
324 views

How can I use “select distinct” and have a range for my rows? [closed]

I wrote this code in PL/SQL developer and was wondering how I could have one row per range of t.ttt in the select distinct columns. Here's the SQL: select count (t.aaa), sum (t.bbb) from xxx t where ...
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2answers
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How do I force a JOIN to use a specific index in MySQL?

I have a query that JOINs 2 tables; lineitem and part, select sum(l_extendedprice* (1 - l_discount)) as revenue from lineitem force index for join (l_pk), part where ( ...
14
votes
3answers
37k views

Pivot rows into multiple columns

I have a SQL Server instance that has a linked server to an Oracle server. There is a table on the Oracle server called PersonOptions which contains the following data: ╔══════════╦══════════╗ ║ ...
2
votes
1answer
629 views

Help with SELECT queries

I need help with some queries. I struggled do find out how to do it, but I think I finally caught on or at least got the results I was looking for in the database. These are the tables (given by my ...
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3answers
1k views

Usefulness of a multi-attribute index

If an index has more than one attribute in it, is there any speed gained in a select statement whose where clause uses one of the attributes in the index? For example, take a table T with an index on ...
1
vote
1answer
341 views

SQL Server - Ignoring object dependencies to copy a DB (despite some column referenced in a sproc no longer existing)

First of all apologies for the novel but there's a lot to explain... We have over 100 databases for our product, 1 per server, each of which has variations on other ones (ideally they should all be ...
4
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0answers
152 views

How to Audit for Access with Cross Database Ownership Chaining

I've just joined the data team of a new company and we have a large SQL Server environment (100+ instances) and cross database ownership chaining is on by what I gather is a necessity. I'm looking for ...
13
votes
2answers
28k views

MySQL: Tree-Hierarchical query

SUB-TREE WITHIN A TREE in MySQL In my MYSQL Database COMPANY, I have a Table: Employee with recursive association, an employee can be boss of other employee. A self relationship of kind (SuperVisor (...
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2answers
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list tables that are missing primary/foreign key in postgresql database

I've seen a ton of queries to list primary and foreign keys but how can I query for tables missing primary and foreign keys? PostgreSQL 8.4 and 9.x versions
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2answers
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Joining 4 tables and 2 counts

I have four tables. UserMaster ---------- UserKey - PK UserName UserID - UNIQUE UserLogTransaction ------------------ UserID - FK:UserMaster.UserID LoginTime LogoutTime CallCenter ---------- ...
4
votes
1answer
5k views

query to identify all data types used in postgresql database tables

I don't want to know all data types, just all data types used in my database. Can this information be queried? PostgreSQL 8.4 and 9.x versions I currently need to know all data types for over 200 ...
3
votes
1answer
6k views

DB2 Defining remote database alias

I'm using DB2 9.7.0.3 for AIX. I want to select data from a remote database, also running DB2 9.7.0.3 for AIX, and insert it into the local database I'm connected to. I believe the query for this ...
2
votes
2answers
609 views

Execution plan flips Filter and Execute Scalar when using the PK, causes cast to fail

I have some data tables that where imported in from a flat file source so everything is varchar(max) except FileRecordID which is a int that hold the row number the data came from in the flat file ...
3
votes
1answer
7k views

Get week/month data

There is a table (MySQL). It's simplified structure: day DATE val INT UNSIGNED I need the average val for: every week containing a date from the table; every month containing a date from the ...
3
votes
2answers
799 views

How to concatenate a column after x rows?

I have a table with columns object varchar(255), frequency tinyint(3) unsigned, I want to concatenate the objects if the sum of frequencies reach a value. Currently I am doing this in PHP as .. ...
2
votes
2answers
7k views

SQL set allowed values for a column

I want to make an ALTER TABLE expression which adds a new column and sets a default value and additionaly defines the allowed values for that column. It's a text column, and allowed should be only '...
2
votes
2answers
7k views

Oracle 11g: “With Clause” very slow

I have written a query utilizing Oracle's with clause. I have identified one particular with clause in a larger query to be really, really slow. Here are three versions of the same query, they all ...
1
vote
1answer
139 views

Does Microsoft Security Bulletin MS11-049 affect SQL Server 2008 SP3?

The security bulletin does not list SQL Server 2008 SP3 under affected software but it came out prior to that service pack. We are running SP3 but this issue is still showing up on a vulnerability ...
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2answers
3k views

SQL Server - How to know when a database has been restored

I'm using sql server 2008, and I would like to know if a specific database has been restored from a device and when did it happened. Is it possible?
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0answers
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Dynamically Converted rows into columns (Pivoting)

Query SELECT Performparam.performparam_Name,studfeedback.studfeedback_Rating, SUM(studfeedback.studfeedback_Rating) AS total, COUNT(studfeedback.studfeedback_Rating) AS totastudents, **...
2
votes
1answer
1k views

SQL Server Maintenance Plan multiple database backups in a single folder

I am using SQL Server 2008 R2. I am trying to create a maintenance plan which backs up multiple databases into one single folder for a day. For ex. I need to backup db1, db2, db3 and dump all these 3 ...
4
votes
2answers
246 views

How to best encapsulate monetary values in a database

I am working on a multi-currency application. For the purpose of simplifying this question, we will not be considering currency conversion (hence I have deliberately left AsAt : datetime out of the ...
5
votes
3answers
11k views

Correct way to design a shopping cart websites database

I am in a web applications course. My instructor really didn't like the layout of my database, saying it was incorrect in pretty much every way. Fast forward 2 months when I'm remaking the website in ...
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2answers
181 views

We are running database maintenace with indexing the system, indexing fails due to locking?

We have been trying to do re-indexing in our system, there are users still using the database during the indexing. While doing index for certain tables there is failure of indexing this seems to be ...
2
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1answer
3k views

Sybase SQL Anywhere 12 - Get all indexes which are unique -> ambigious sysindexes error

we are using a Sybase SQL Anywhere 12 db. In the db there are indices, which are unique, but shouldn't be unique. Therefore I search for a quick way to list all tables with unique primary keys. I ...
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2answers
617 views

SQL queries break our game! (Back-end server is at capacity)

We have a Facebook game that stores all persistent data in a MySQL database that is running on a large Amazon RDS instance. One of our tables is 2GB in size. If I run any queries on that table that ...