DO NOT USE this for questions targeting Microsoft SQL Server, use the tag sql-server instead. "SQL" is an acronym for "Structured Query Language", it is used in relational database management systems (RDBMS) to query, update, delete, and insert data as well as modify the structure of the database. ...

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How do I insert a row which contains a foreign key?

Using PostgreSQL v9.1. I have the following tables: CREATE TABLE foo ( id BIGSERIAL NOT NULL UNIQUE PRIMARY KEY, type VARCHAR(60) NOT NULL UNIQUE ); CREATE TABLE bar ( id BIGSERIAL ...
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3answers
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Does disconnecting the network stop a query?

I recently executed an update query against 100,000 records. I realized I'd made a mistake while the query was running and quickly unplugged the network cable. Does the update query stop ...
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3answers
1k views

SQLITE: A problem of tags and products

I'm searching for a way to create a query to do the following: Let's consider 3 tables: products: List of products tags: list of tags tag_ties: table used to associate a tag to a product Let's ...
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6answers
433 views

Backing up SQL DB more frequently

I currently have a scheduled task that fires off each night at 2 AM that calls SQLCMD.exe and passes it a .sql script to run for the backup (shown below). We're a pretty small company with growing ...
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5answers
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Query Running Differently on SQL 2005 vs SQL 2008R2

At my office, we have a query that is pretty ugly, but runs pretty well in production and in the development environment (20sec, and 4sec respectively). However in our testing environment it takes ...
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6answers
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Find “n” consecutive free numbers from table

I have some table with numbers like this (status is either FREE or ASSIGNED) id_set number status ----------------------- 1 000001 ASSIGNED 1 000002 FREE 1 000003 ...
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2answers
11k views

How do I show the binlog_format on a MySQL server?

How do I show the binlog_format on a MySQL server? And if I dont like it how do I set it to XX permanently? Where XX is STATEMENT, ROW or MIXED.
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5answers
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Oracle sort varchar2 column with special characters last

How can I sort in Oracle a Varchar2 or NVarchar2 column to be in my own custom defined order. Or are any existing options available that will put letters first, then numbers, then all special ...
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6answers
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How do you submit a List of items to a Stored Procedure to limit results? [duplicate]

Possible Duplicate: Passing array parameters to a stored procedure Lets say you want to filter results by a List of uniqueidentifiers such that your SQL statement would read: WHERE ...
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4answers
178 views

SQL Server 2005/8 Query Optimisation Hints

I'm looking at educating a team on writing better SQL Server queries and was wondering what people's best hints were for improving performance. For instance I once had a DBA who insisted that ...
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4answers
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What does the term “projection” refer to in an SQL query (or view definition)

In Oracle's document The Query Optimizer, under View Merging, I found the following information The view merging optimization applies to views that contain only selections, projections, and ...
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235 views

Are “out of the row” fields read when a clustered index is used?

I know that when VARCHAR(MAX)/NVARCHAR(MAX) columns are used the data is stored out of the row - the data row will have a pointer to another location where the 'large value' is stored. I have the ...
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How to check if a subquery has exactly one distinct result and a specified value concisely?

I found myself writing the following: select 'yes' where exists(select * from foo where val=1) and not exists(select * from foo where val<>1); and wondering if there is a more concise way ...
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3answers
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How to do a case sensitive search in WHERE clause?

I want case sensitive search in SQL query. But by default, MySQL does not consider the case of the strings. Any idea on how to do a case sensitive search in SQL query?
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votes
3answers
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SQL Server - Multiple running totals

I've got a base table with transactions and I need to create a table with running totals. I need them to be per account and and also have a few running totals for each account (depending on the ...
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3answers
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Is there a standard implementation of a Users Database?

I need to implement basic personalized user functionality for my website. Is there a standard structure for databases of this type? Like is it common practice to have all user info and data in a ...
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3answers
474 views

Where to start with Oracle?

This question only needs one answer: a list of great resources for getting started with Oracle, including Database Administration, PL/SQL and SQL. You may find your question has been closed as a ...
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4answers
991 views

overstating field size in database design

I have some fields for my tables that are strings and at the moment, most of the field size have pretty high character limits. For instance, 100 char for the street name. Is there a penalty for using ...
8
votes
2answers
195 views

Non-Clustered Indexes - keys and nonkeys

I just want to make sure I'm on the right track with these concepts, so any feedback would be greatly appreciated. Here's my theory from the query I've just optimised, through a process of trial and ...
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2answers
385 views

Do agile software development approaches apply to SQL?

I would like to learn if agile software development methods/principles/patterns are valid to SQL programming as well. If yes, where would be a good place to start learning about that? Are there any ...
8
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3answers
7k views

Why are NULLs sorted first?

Why is it that when we have a NULL value in a column and we order by the value ascending, the NULLs are sorted first? select 1 as test union all select 2 union all select NULL union all select 3 ...
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votes
3answers
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How to Best Implement nearest neighbour search in mysql?

So, in short, What should be the data type of latitude and longitude? What SQL command I should call to get the first 100 nearest restaurants for example? Detail: I have 100k biz record each with ...
8
votes
3answers
2k views

What are the alternatives for an ORDER BY clause in a View?

This question just had to be in this site :) ORDER BY is forbidden to use in a view, as I understood because of the possibility for multiple order by's when using this view. I know that there are ...
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3answers
3k views

Oracle: How do I query a Hierarchical table?

Background This is for the construction of some views we'll be using for reporting. I have an table of locations, the key fields being "location" and "parent". The structure that these two fields ...
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Deleting all duplicates

I am trying to delete all the duplicates but keeping single record only (shorter id). Following query deletes duplicates but take lot of iterations to delete all copies and keeping original ones. ...
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4answers
2k views

How can I optimize this MySQL query further?

I have a query that is taking a particularly long time to run (15+ seconds) and it is only getting worse with time as my dataset grows. I have optimized this in the past, and have added indices, ...
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5answers
210 views

What is the best way to find out how many records do not have a proper phone number in SQL Server?

I have a field that people historically could use to freely supply a value. I need to identify the records which do not have an appropriate value so I can clean them. I've been looking around in SSIS ...
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votes
1answer
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Deleting large amounts (4 million rows) of mysql data efficiently, on a very regular basis

We have a mysql table that at any given time has about 12 million rows. We need to delete old data to keep the size of the table somewhat manageable. Right now we are running this query daily, at ...
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votes
2answers
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function hangs with null case operation

I created a function that accepts a start and end date, with the end date being optional. I then wrote a CASE in the filter to use the start date if no end date is passed. CASE WHEN @dateEnd IS NULL ...
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votes
3answers
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How to boost performance of virgin queries in MS SQL Server?

I have ASP.NET web site that does it's own independent caching of data and data does not change for long periods of time, so it does not need to query SQL Server second time with same query. I need to ...
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votes
3answers
2k views

Is there a way to programmatically script all objects associated with a given table?

I know that in SQL management studio I can right click a table/trigger/key and script object as.... Is there a way to do this programmatically, given an object's name? If so, is there a way to find ...
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5answers
846 views

SQL Server 2008 and extended properties [closed]

In SQL Server, what do you guys use extended properties for? Some articles and blogs are suggesting they be used for self-documentation of the database and its objects but I can't see this being used ...
8
votes
3answers
6k views

When should indexes be dropped and recreated?

We are constructing a data warehouse that initially will be 1 TB and will grow around 20gigs every month. For certain tables we are doing daily ETL processes and others we are doing weekly/monthly. ...
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2answers
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Table not getting created under dbo schema

When creating tables in SSMS, I've realized that if you execute the following statement: CREATE TABLE [tableName]; the table will be created under your own schema (and not dbo). So in order to ...
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2answers
5k views

How to retrieve foreign key constraints data

I'm looking for a query allowing to retrieve foreign key infos (each line: referrencing table & field, referrenced table & field) of an entire schema. I've found this, but does not gives all ...
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2answers
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How to delete a procedure which name is ambigous?

I am using informix... I dont know how i did it, but there are two procedures with the same name in my database. When i try to remove them with a DROP PROCEDURE myProc; then i get a error message ...
8
votes
1answer
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Deadlock when update different rows with non-clustered index

I'm solving a deadlocking issue while I noticed the lock behavior is different when I use clustered and non-clustered index on the id field. The deadlock issue seems to be solved if clusted index or ...
8
votes
1answer
944 views

IO_STALL question and understanding

I am collecting IO_STALLS from sys.dm_io_virtual_file_stats every 5minutes and then doing a delta to see which files are being affected most by IO. In one 5min period I get a delta of 5826331 ms ...
8
votes
3answers
55k views

SELECT DISTINCT on one column, while returning the other columns?

I have a query which uses three lookup tables to get all the information I need. I need to have DISTINCT values for one column, however I also need the rest of the data associated with it. My SQL ...
8
votes
3answers
976 views

SQL Server query slow when paginated

I am seeing some strange behaviour with the following T-SQL query in SQL Server 2012: select Id FROM dbo.Person WHERE CONTAINS(Name, '"John" AND "Smith"') order by Name Executing this query alone ...
8
votes
1answer
2k views

Is there an execution difference between a JOIN condition and a WHERE condition?

Is there a performance difference between these two example queries? Query 1: select count(*) from table1 a join table2 b on b.key_col=a.key_col where b.tag = 'Y' Query 2; select ...
8
votes
6answers
7k views

SQL Query Formatter [closed]

Are there any (Linux based) SQL Query Formatting programs/plugins/extensions? I use PostgreSQL and MySQL but other DB's are welcome as well. I can use a VM to test with but would prefer a Linux ...
8
votes
4answers
128 views

What are the trade offs for incrementing ids vs. fulltext keys for foreign key designs?

In a lot of relational database designs there are fields that are referenced in other tables. For example consider a user table with a unique username and a second table storing address data. One ...
8
votes
2answers
900 views

LNNVL Justification

LNNVL is an oracle built in function that returns TRUE for conditions evaluating to FALSE or UNKNOWN, and returns FALSE for conditions evaluating to TRUE. My question is what would be the benefit of ...
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votes
1answer
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What are the security implications of sp_executesql?

By default, in SQL Server, the [public] role has EXECUTE rights on sp_executesql. However, I've inherited a database server where the previous DBA has revoked the EXECUTE right on sp_executesql. As ...
8
votes
2answers
15k views

SQL Server backup failing. Error: 3041, Severity: 16, State: 1

First of all, I'm very new at stackexchange, so please bear with me. I'm running a SQL Server 9.0.4060. My problem is: my SQL Server backup keeps failing on a lot of the databases. The Maintenance ...
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votes
3answers
4k views

SQL Server 2008 datetime index performance bug

We are using SQL Server 2008 R2, and have a very large (100M+ rows) table with a primary id index, and a datetime column with a nonclustered index. We are seeing some highly unusual client/server ...
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1answer
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Friends relations in MySQL

I'm developing a friendship relation in MySQL where friend relation is mutual. If A is friend of B, then B is friend of A. If one of the users end friendship then relation drops. I want to learn which ...
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2answers
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How does using separate schemas affect SQL Server 2008 performance?

I want to use separate schemas for objects with different purposes in our SQL Server 2008 database. Right now we use a fairly mind-numbing naming convention to indicate the purpose of a table or ...
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2answers
1k views

Handling time zones in data mart/warehouse

We are starting to design the building blocks of a data mart/warehouse and we need to be able to support all time zones (our clients are from all over the world). From reading discussions online (and ...