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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optimize the query with big and low cardinality

I have big enough dataset and few joins to get them all with help next query: SELECT DISTINCT c.c_id FROM c_active z1 INNER JOIN cs c ON (z1.cv_id=c.cv_id) INNER JOIN indi i ON (c.m_id=i.m_id) INNER ...
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143 views

type recognition with MonetDB, *create* tables from CSVs

I am confused whether you can copy records into a new table in MonetDB. The official documentation seems to talk only about copying into existing tables. I have quite a large universe of billions of ...
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1answer
1k views

Is it possible to query value of SQLNET.EXPIRE_TIME parameter?

Can somebody advice whether it is possible to query for current value of SQLNET.EXPIRE_TIME parameter in Oracle 11 DB? Should select * from v$parameter return value of SQLNET.EXPIRE_TIME (if it ...
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Cascading Inserts in MySql

I have a users table that has a one to one relationship to a user_preferences table (primary foreign key user_id). When a new row is added to the users table (new id added), is there a way to setup ...
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202 views

SQL from/where or join?

I was wondering performance wise what would be faster a join or a from and where query. I am trying merge and update query but performance is terrible?
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957 views

sql server 2008 - controlling size of log file

I am getting this error. Msg 9002, Level 17, State 4, Line 2 The transaction log for database 'SalesDWH' is full. To find out why space in the log cannot be reused, see the log_reuse_wait_desc ...
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9k views

Stored Procedure to return dynamically created table data

Quick back story, we are working with an outside vendor that has a survey system. The system is not necessarily designed the best in that when you create a new survey and the system creates a new ...
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1answer
6k views

Order by column should have index or not?

I have added indexes to table which are used for searching result. I am showing results by ASC or DESC order. So that column should have index or not? I have 2 more indexes on that table. How ...
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2answers
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Updating 700 million rows to same value

I've got a data warehouse (oracle) where I need to set a column to the same value for all 700 million rows. I don't have admin access, or access to an admin, so this needs to be accomplished with ...
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3answers
9k views

How export a sql server 2008 diagram to PDF filetype?

I want to have a export from my database diagram to PDF or image types.How can I do this? I worked with sql server 2008 R2.
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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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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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Database design: Dividing multiple identical tables, good or bad?

I am very new at SQL and databases in general. I only use them for the occasional homework so I haven't even tried to master them. I have seats at a theater, the seats are divided into 4 main areas ...
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2answers
324 views

Why do we have SHRINKDATABASE command in SQL Server

I have read across the internet where Finest Developer says shrinkdatabse should be avoided as it causes increase in fragmentation and decrease in performance . So i would like to know from you guys ...
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4answers
4k views

Do SQL Server stored procedures cache data results?

I have heard this from friends, but I never investigated whether this is true. Is it true that the data results of an executed query are stored in cache? I mean, if I have a stored procedure like : ...
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4answers
4k views

How do I do a complex GROUP BY in MySQL?

I have a table that contains several keys into other tables (where each key is comprised of multiple columns). I would like to be able to group rows together that have an equal key, but I don't want ...
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4answers
494 views

Is a join optimized to a where clause at runtime?

When I write a query like this... select * from table1 t1 join table2 t2 on t1.id = t2.id Does the SQL optimizer, not sure if that is the correct term, translate that to... select * from table1 ...
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1answer
239 views

Table order in Join Query

if i say: Table1 left join Table2 is it the same as saying Table2 right join Table1 ? In other words, should i expect to get the same results from 2 identical queries where the only thing that is ...
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2answers
1k views

Database locking issues?

I have run into a transaction related issue on a SQL Server 2008 production database. A brief overview is that we have a website that has numerous concurrent users around the state, who do GUI type ...
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4answers
2k views

Multiple operations using WITH

Is there a way to execute multiple operations using the WITH statement? Something like WITH T AS ( SELECT * FROM Tbl ) BEGIN OPEN P_OUTCURSOR FOR SELECT * FROM T; SELECT COUNT(*) INTO ...
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2answers
951 views

Using totals on aggregates to improve performance

I have two tables: details and totals of these details. Details (Slow solution): select OrderId = r.OrderId , TotalQty = SUM(r.Quantity) , ...
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1answer
2k views

Difference between count(*) and count(1) in mysql?

In MySql we can count the total number of records by using count(1) or count(*). Is there any technical difference between them?
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4answers
2k views

Checking if 2 tables ( on different servers ) have the same exact data

So it seems that the company who is hosting our SQL Servers has been having some trouble with the replication from the production server to the backup server... I believe some of the tables have been ...
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2answers
519 views

SQL Server configuration / specification recommendations and advice!

I am about to deploy a new server at work as follows: Dell T610 2 x Xeon 2.53 Quad core 24 GB RAM 1 x Perc H700 RAID controller with 1GB Non Volatile memory 8 x 300GB 15k SAS Hard drives I am looking ...
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1answer
445 views

Dealing with temp tables when I have not control over db variables

I have no control over things like tmp_table_size and max_heap_table_size, and so as our tables grow the time taken by queries requiring temp tables is growing geometrically. I am wondering if there ...
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2answers
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Migrate all databases from one SQL Server 2005 to another

We have a production SQL Server 2005 server on which we are hosting 200 databases. We want to host these databases on our new server. On new server SQL Server 2005 is installed and is ready. I want ...
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1answer
172 views

Optimizing concurrent updates in Postgres

I'm running concurrent Postgres queries like this: UPDATE foo SET bar = bar + 1 WHERE baz = 1234 Each query affects the fixed K number of rows, and I can't find a way to enforce the order in which ...
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146 views

Order by distance

If I have a query returning nearby cafes: SELECT * FROM cafes c WHERE ( ST_DWithin( ST_GeographyFromText( 'SRID=4326;POINT(' || c.longitude || ' ' || c.latitude || ')' ), ...
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325 views

Order of columns in a compound index in PostgreSQL (and query order)

I have a table with 50K rows. It is actually a PostGIS table. The query has 4 parts (1 mandatory) (3 Optional) intersection box (a geography rectangle) with 4 lat,long (I use st_intersects) ...
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1answer
970 views

SQL Server 2008 R2 Upgrade (Express to Standard) fails. No “Select Instance”

Hello there, i got stuck in the progress of upgrading 3 systems from SQL Server 2008 R2 Express Edition --> SQL Server 2008 R2 Standard Edition Problem: The Option "Select Instance" in the ...
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1answer
4k views

Syntax of INNER JOIN nested inside OUTER JOIN vs. query results

TLDR; If you look at the 2 execution plans, is there an easy answer to which is better? I purposefully did NOT create indexes so it's easier to see what's happening. Following up on my previous ...
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1answer
1k views

How do I get the aggregate of a window function in Postgres?

I have a table containing a two columns of permutations/combinations of integer arrays, and a third column containing a value, like so: CREATE TABLE foo ( perm integer[] NOT NULL, combo integer[] ...
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votes
2answers
176 views

Checking a wide table for nulls [duplicate]

Possible Duplicate: Test if any fields are NULL I am new here. I have a table with 70-odd columns. Is there a way I can check the number of rows with at least one null value in any column ...
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1answer
6k views

oracle format specifiers: to_number vs to_char

SQL> select TO_NUMBER(123.56,'999.9') from dual; select TO_NUMBER(123.56,'999.9') from dual * ERROR at line 1: ORA-01722: invalid number SQL> select TO_CHAR(123.56,'999.9') ...
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1answer
58 views

Determining what query was called

I want to reverse engineer what exactly happens to the MySQL database when a product is added in Magento. I will have to reproduce the query, because I would like to manually enter new records using a ...
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3answers
216 views

Join table on some conditions

I've got a table called activities. And a table messages. Activity has many messages, and one message has one activity. This are the message columns : id sender_id receiver_id body activity_id I'm ...
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1answer
127 views

Do SQL Server Views update their data types automatically based on what tables feed them?

Someone mistakenly created a bunch of nchar fields in database tables. I noticed this, and after examining the issue, we're moving these fields to nvarchar types and trimming the values inside. In my ...
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4answers
2k views

Select rows based on latest date with multiple joins

I have this query (SQLFiddle): SELECT c.name, a.user_id, a.status_id, a.title, a.rtime, u.user_name, s.status_name FROM company c LEFT JOIN action a ON a.company_id=c.id LEFT JOIN user u ON ...
3
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1answer
569 views

How to separate out individual sql statements from Oracle SQL script for execution from java code

I have Oracle DB 11g Enterprise Edition and I want to execute sql script from my java code. I am reading this sql script from a .sql file and the script contains statements such as create table, ...
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1answer
942 views

How does Log shipping knows to keep track

I have set up log shipping between 2 SQL Servers (SQL Server 2008 and SQL Server 2012). At first i took a full backup of the first one and restored it on the other one and than i set up the log ...
3
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1answer
338 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. ...
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5answers
3k views

How to get the total days per month between two dates?

Given two dates like 20120302 and 20120605 I need to get a list of Months and the total days in those months that fall between those two dates, like so: March 28 April 30 May 31 June 03
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2answers
11k views

Using Same CASE WHEN Conditions For Multiple Query Columns

Is there a "better" way to rewrite a SELECT clause where multiple columns use the same CASE WHEN conditions so that the conditions are only checked once? See the example below. SELECT CASE ...
3
votes
3answers
481 views

SQL JOIN Syntax in MS SQL

I have been taught in my MSSQL classes, this is how to join two tables select * from FirstTable A JOIN SecondTable B on A.ID= B.ID Now in my professional life, I came across JOIN queries like ...
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3answers
992 views

Speed up search across multiple columns

We have a table: user_info (user_id,domain_id,first_name,middle_name,last_name,work_place,.,.,.) Now, we have a user search that search across three columns first_name,last_name and work_place. ...
3
votes
5answers
6k views

Copying Oracle 11g express Database from one server to another

Basically, I am a MS-SQL developer,and relatively new to Oracle. Even after great deal of research, I was unable to find any way of copying entire database from one server instance to another. In ...
3
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2answers
3k views

SQL Server 2008 T-SQL select hanging, but not dead locked

This is a pretty strange issue so bear with me. I have a stored proc that does some heavy duty processing. When it runs well it usually takes a few minutes depending on server load, but occasionally ...
3
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2answers
494 views

Transaction Log 16GB on 2MB database [duplicate]

Possible Duplicate: Why is My SQL Server Transaction Log Growing or Running out of Space? The transaction log in one of my client's databases is 16GB, when the database itself is only 2MB. ...
3
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2answers
1k views

Can the sorting from an ORDER BY statement be saved explicitly with only one UPDATE statement?

I have this table: SELECT * FROM items id | item | position ---|-----------|---------- 1 | USB cable | 0 2 | SD card | 4 3 | Mouse | 2 4 | Keyboard | 0 5 ...
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2answers
551 views

Testing Query Speed

When I'm running a query for the first time, it takes x miliseconds to be executed. When I run it the second time it takes a lot less time. I assume that it is some caching involved in this mechanism, ...