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

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11
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3answers
12k views

Why is an aggregate query significantly faster with a GROUP BY clause than without one?

I'm just curious why an aggregate query runs so much faster with a GROUP BY clause than without one. For example, this query takes almost 10 seconds to run SELECT MIN(CreatedDate) FROM MyTable WHERE ...
10
votes
1answer
17k views

Why does a query run slower in a Stored Procedure than in the Query window?

I have a complex query which runs in 2 seconds in the query window, but about 5 minutes as a Stored Procedure. Why is it taking so much longer to run as a stored procedure? Here's what my query looks ...
8
votes
4answers
30k views

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?
6
votes
2answers
9k views

SQL query slow-down from 1 second to 11 minutes - why?

Question: I'm porting the below query (listing tables by foreign key dependencies) to PostGreSql. WITH Fkeys AS ( SELECT DISTINCT OnTable = OnTable.name ,AgainstTable = ...
1
vote
1answer
598 views

Right Tool for Data Mapping in Relation to Business Intelligence

When you are working as a BI developer you also need to create a data mapping between dimensional modeling and source system. What kinda application to visualize a data mapping?
1
vote
1answer
778 views

Why is the output of this query being returned like this?

I have a T-SQL query : select CAST(0 as float(53)),CONVERT(nvarchar(max),CAST(0 as float(53)),128) the output of which is 0,0.0E0 Can some one explain why it is not 0,0 ? The database is SQL ...
0
votes
1answer
196 views

Sensible data management tool for importing and exporting of large data files

I am looking for some sensible suggestions on data management tools for large data files. I have been experimenting aith excel and access only to find that access has limitations on import files size ...
1
vote
3answers
557 views

changing a range into discrete values for a field in oracle

I have a data table that contains records like this: ZIP Ground Air 010-041 005 305 150-163 004 304 As I have it right now, it's actually an excel file but I eventually need to ...
3
votes
3answers
2k 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. ...
2
votes
1answer
322 views

Review Technical ETL process for knowledge management

I'm looking for source code and all related component/material to review technical ETL process between source database and Data Warehouse in order to increase my knowledge in technical Business ...
2
votes
4answers
2k views

Remove sub-string from WHERE clause

I have a stored procedure that is using the SUBSTRING function in the WHERE clause. SELECT DISTINCT ColumnBB, ColumnCC FROM TableAA WITH (NOLOCK) WHERE SUBSTRING(ColumnAA, 1, 17) = @VariableA; ...
5
votes
2answers
227 views

Product of n Rows

From this data (assuming the number of rows is not known in advance): with q1 as (select mod(ora_hash(level),5) c1 from dual connect by level <=4) select * from q1; /* C1 -- 2 1 4 1 */ I ...
3
votes
3answers
5k views

Can Oracle SQL developer export data as a set of Update commands?

Oracle SQL developer gives us the option of exporting data. But it only gives us the option to export as a set of Insert statements. I have two databases with a mirrored table. One of them has some ...
0
votes
1answer
663 views

MySQL table with multiple values in one field

I'm building a database for a real estate company. The real estate properties are managed by sales people using a CodeIgniter website. How should I proceed with the database design for this table? ...
4
votes
1answer
894 views

How to query EndDate value from ReportServer..Subscriptions.MatchData

In SQL 2008 R2, I'm putting together some administrative queries on SSRS metadata to check proper configuration, and other sorts of proactive things. While querying the ReportServer db, I've been ...
2
votes
1answer
3k views

MySQL UPDATE to replace text in LONGTEXT field

I have a WordPress table wp_posts and I'd like to run an UPDATE that will replace a url from my old domain to my new domain. For example, let's say that one record in the field post_content has the ...
6
votes
3answers
9k views

Test if any fields are NULL

I'm trying to figure out an easy query I can do to test if a large table has a list of entries that has at least ONE blank (NULL / empty) value in ANY column. I need something like SELECT * FROM ...
2
votes
2answers
3k views

Adding Timestamp to Exported Filename in SQL Server Management Studio

I am exporting to a CSV using a job with xp_cmdshell. I need the filename to include a timestamp. The code I currently have is... EXEC xp_cmdshell 'bcp "SELECT * FROM dbo.tablename" queryout ...
2
votes
2answers
3k views

SQL Server Management Studio .bak files

I'm new to SQL Server SMS and need help. I have been asked to check that .BAK files restored be checked using SELECT queries in SQL SMS. I have tried to create a new database but get the error ...
0
votes
3answers
1k views

Is it possible to edit sys.messages texts?

Is it possible to add a new language to SQL Server 2008 and edit SQL error messages with message_id less than 50000?
1
vote
2answers
73 views

stack data into a single column

SELECT * would result in: course_id + group ----------------- 1 + SE123 1 + BA134 2 + SE213 3 + SE223 3 + BA344 4 + SE222 I would like it be like ...
2
votes
1answer
349 views

Query logical processing phases while mixing old and new join syntax

Could anyone clarify why order of tables in FROM matters if I mix old and new syntax for joining tables? For example, SELECT * FROM table1 a, table2 b INNER JOIN table3 c ON (c.a_id = a.id) -- ...
6
votes
1answer
150 views

Are there any fully declarative implementations of SQL

I was recently bitten by a bug ( in my code ) where these two queries had drastically different runtimes: select * from smalltable st inner join bigtable bt on st.btid = bt.btid select * from ...
1
vote
3answers
7k views

How should I Schedule SQL Server 2008 queries to run every month?

I need to schedule some queries to run at the beginning of every month (for monthly reports) and I read that creating a JOB in sql server 2008 was the way to go. Unfortunately, I don't have the ...
2
votes
3answers
2k views

performance of multi field primary key or 'contrived' 'semi artificial' key

This is not a question regarding the benefits or otherwise of using an artificial auto increment key in any given table against using a multi-field 'primary key'. That discussion (or argument) can ...
5
votes
1answer
4k views

Dropping unique constraint on PostgreSQL table taking 10+ hours

We have a PostgreSQL database with a fairly large table (~50 million rows). The table has a unique constraint across several columns, each of which is indexed. For context, I recently deleted about ...
9
votes
4answers
6k views

Do you know an easy way to generate one record for each hour of the past 12 hours?

I have a report that shows the count of events for the past 12 hours, grouped by the hour. Sounds easy enough, but what I am struggling with is how to include records that cover the gaps. Here is an ...
3
votes
3answers
113 views

A join aggregate behaviour I can't understand

Query 1: SELECT c.class_id, SUM ( CASE WHEN s.student_id IS NULL THEN 0 ELSE 1 END ) as total_students FROM classes c LEFT JOIN students s ...
1
vote
1answer
658 views

Execute Stored Procedure against CMS from within a SQL Server Agent job

Is it possible to execute a stored procedure (or any T-SQL) against a Central Management Server (CMS) via a SQL Agent job? The idea here is to exercise the CMS to hit all the registered instances ...
2
votes
3answers
167 views

SQL Query Against Previous SQL Query Results

Is there an SQL database (for C#) that allows me to query against on-disk database and then later on (probably offline at client side) query against the in-memory result set using SQL? I basically ...
23
votes
4answers
9k views

SQL Server “empty table” is slow after deleting all (12 million) records?

I have a SQL Server 2008 instance with approximately 150 columns. I have previously populated this table with approximately 12 million entries, but have since cleared the table in preparation for a ...
7
votes
2answers
10k views

SQL Server: query performance (search 2 million rows)

Got an interesting one for all of you SQL guru's out there. Now this search is only taking a couple of seconds, but it's quite intensive and there must be a better way. Maybe I'm expecting too much? ...
4
votes
2answers
900 views

Splitting a column in two and returning a summary of results

Lets take a very simple table Department | Staff Name ---------------------|--------------- Web - Electronics | Matthew Store - Electronics | Mark Web - Home | Luke Store - ...
1
vote
2answers
40k views

Error: Specified cast is not valid. (SqlManagerUI)

I am trying to restore database created on server to my localbox however i am getting 'Error: Specified cast is not valid. (SqlManagerUI)' error message. Server Info: Windows Server 2008 Standard ...
3
votes
3answers
125 views

~15 data sets w/ 25k rows & ~20 columns + quick one time reports = Access VS SQL?

I am working with around 10-15 datasets each containing around 25,000 rows and around 20 columns. Data is text in name/adress/desc and the rest numbers. I need to be able to calculate certain fields, ...
14
votes
1answer
737 views

Poor SQL Server performance when management studio closed

I've noticed a strange behaviour of SQL Server 2008 r2 express: usually my query execution time is ~650ms, but if I open Management Studio and run any simple query (for example SELECT * FROM ...
7
votes
5answers
25k views

Full Outer Join in MS Access

I have two staff lists: List A: StaffID Supervisor ==================== 0001234 NULL 0001235 0001234 0001237 0001234 0001239 0001237 and List B: StaffID Supervisor ...
0
votes
1answer
7k views

sql server - could not allocate space for object

I am trying to retrieve the first 1000 records of my view and am getting this error message: Msg 1105, Level 17, State 2, Line 2 Could not allocate space for object 'dbo.SORT temporary run ...
4
votes
4answers
2k views

Help with Query. Finding records that have the same relationships (MySQL)

I have a table of Listings that has a many to many relationship with a Taxons table. The table structure looks like this: listings ---------------- id (int) name (varchar) listings_taxons ...
6
votes
3answers
9k views

How to make sure that simultaneous INSERT and SELECT on one table won't make a deadlock?

I have the following table in my SQL Server 2008 database: CREATE TABLE [dbo].[SomeTable] ( [Id] [bigint] IDENTITY(1,1) NOT NULL, [Column1] [varchar](30) NOT NULL, [Column2] [varchar](30) ...
11
votes
2answers
3k views

Tombstone Table vs Deleted Flag in database syncronization & soft-delete scenarios

I need to keep track of deleted items for client synchronization needs. In general, is it better to add a tombstone table and a trigger that tracks when a row was deleted from the server database - ...
1
vote
1answer
74 views

How can this data be joined?

Definition: table_A table_B id,description id,description,id_table_A Column id_table_A is a foreign key to the primary key of table_A and is not mandatory. Sample data: ...
5
votes
2answers
704 views

Large accounting table, best way to partitioning by two dates

I need to create a log table to stores the connections to out network (last 3 years, after that the log will go into backup). The hardware/software used is proprietary, and for accounting it just call ...
4
votes
1answer
655 views

How to change database owner for login and database created inside stored procedure?

I have a signed stored procedure that creates a new database, a new login and assigns the new user to be the owner of the new database. Well my SProc creates the new login and new database but will ...
2
votes
1answer
233 views

Can I use a Clob as a table key (from Java)?

Following a suggestion made to another question to store large amounts of text: can one use a CLOB as primary key field (i.e., from Java's DataNucleus implementation of JDO)? I know it is probably a ...
1
vote
1answer
804 views

oracle - does this have the potential to cause a lock?

Note how no commit was done in between each statement. Could this cause a table lock or blocked session? delete from tableblah; insert into tableblah (select * from othertable);
1
vote
1answer
657 views

Unable to connect to MySQL cluster database

I am unable to connect to mysql cluster database after starting my management node, data node, mysql node. I made the necessary changes by adding the loadbalance in the dbURL. But I am not able to ...
1
vote
1answer
2k views

creating a table from a selection and then using group by - oracle sql

I'm working in oracle and I can't figure out what's wrong with this statement. The error it gives me is must name this expression with a column alias CREATE TABLE shipping_costs_grouped AS ...
3
votes
3answers
894 views

Database growing like crazy - what do I do?

I have an Epicor 9 ERP database that I recently was put in charge of (new job). Server is running Server 2008 R2 with SQL Server 2008 R2 64bit. The main production database started at 16gb 7 months ...
11
votes
2answers
13k views

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 ...