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

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4
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How do I remove duplicate records in a join table in PostgreSQL?

I have a table that has a schema like this: create_table "questions_tags", :id => false, :force => true do |t| t.integer "question_id" t.integer "tag_id" end ...
5
votes
0answers
2k views

Is there a Postgres admin GUI that can execute a master file containing multiple sql files

I'm developing a really long script. I'd like to break the script into smaller, more manageable scripts and include each sql file in a master file, then just execute the master file. example: ...
3
votes
3answers
912 views

Sum Up values in a query based on other information

I am trying to grab the sum of 2 columns if 1 column is the same. I currently have a record-set that looks like this: I get these results by running this statement: select distinct a.eventnum, ...
0
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1answer
3k views

SQL update set column = @ parameter

doeas anyone knows how to update a table where column = @parameter WHERE SELECT Basically I have a table with the following values. Table name is UserAttribute ID|Name |Properties| ...
1
vote
1answer
211 views

Query to determine a count by rolling interval

I'm looking at orders and trying to simulate some messageing that we are doing in the query so that Marketing can get a base line for how many responses they might expect if we changed the interval of ...
1
vote
1answer
63 views

Script to get duration

I am new to PostgreSQL. I am trying to write a query which can give me duration of the time. The fields are in the format yyyymmddhhmmss. In between we will get empty fields for Start_Time or ...
2
votes
1answer
491 views

How to Reorganize Microsoft Access Table

I have just taken over a retiring DBA's position and is responsible for migrating the current access database to SQL Server or PostgreSQL. Right now, the table structure is a mess. Instead of ...
2
votes
2answers
187 views

Representing SQL constraints on a table

I have this table: CREATE TABLE `sold` ( `part_ID` INT(11) NOT NULL , `date` DATE NOT NULL , PRIMARY KEY (`part_ID`, `date`) , FOREIGN KEY (`part_ID` ) REFERENCES `part` (`part_ID` ); This ...
0
votes
1answer
415 views

What index to add in case of join by two optional fields

I have query similar to the one below, it joins two tables by field which can have NULL value. The result matchs the data if both tables have the same data or consider the condition as optional. ...
12
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2answers
3k 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 ...
3
votes
2answers
8k views

Database design for an E-commerce website

I am new to database design. I am designing a database for an E-commerce website, there are a lot of products to be updated, but while designing for product specification table I do not understand ...
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4answers
574 views

Mysql - How to Optimize Retrieval Time in a Table

I have query which has 200 million Records in a single table. I am using BTree indexes in my table: mysql> select COUNT(DISTINCT id) from [tablename] where [columname] >=3; ...
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3answers
17k views

How to model inheritance of two tables mysql

I have some tables where I store data and depending on the type of person (worker,civil) that did a job I want to store it a table 'event', now these guys rescue an animal (thereis a table animal). ...
1
vote
1answer
330 views

I would like to query a range of criteria on multiple columns in MySQL

I have 3 columns in a mysql table. I'm using Innodb engine. I want to be able to search for some values on those columns and also anything close to those values. For example : We have 3 columns as ...
2
votes
4answers
11k views

Search every column in every table in Sybase Database

I'm been taxed with the task of creating an application that pulls data from our Micros Point of Sales system. The POS is using a Sybase database running on one of our servers. The database schema is ...
6
votes
1answer
870 views

Does large table variables fill up logs in tempdb?

I'm running into an issue with a DBA who claims that table variables reside in ldf of the tempdb and when large amount of data is loaded into the table variable, the tempdb's logs fill up. The DBA's ...
4
votes
1answer
86 views

Covering Index Question

I have the following query Select Pt.PRODID, PT.INVENTREFID, Inv.ItemName, PT.ItemID, Configid, Pt.QTYSCHED, PT.DLVDATE, Pt.CREATEDDATETIME, pt.SCHEDEND, CASE Left(PT.INVENTREFID, 3) WHEN ...
2
votes
2answers
258 views

Is this relation in 3NF?

I created a relation called Customer and defined as: I just wanted to know if it is in 3NF? My concern is regarding address, since customer may have the same address.
2
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2answers
404 views

SQL Max() revision number

This SQL returns a table with everything unique, which is what I want. However, if there are two (or more) event numbers, I need it to return the line with the highest rev_num for that eventnum. I ...
1
vote
2answers
131 views

Does this query make sense?

I recently migrated a database from Sybase ASE to Microsoft SQL 2008r2. One category of queries that was broken in transit is: SELECT person_id FROM leaveperiods WHERE group_id=146 GROUP BY ...
2
votes
1answer
109 views

What is the equivalent of a “Certificate of Destruction” when using a cloud-hosted database?

We have a Rails application hosted by Heroku and using an Heroku Postgres database. Some of the information we store is considered to be sensitive by our users, and we've been asked if we can provide ...
4
votes
3answers
754 views

Backup strategies for zero data loss

I am working on one project and it has around 100K records. We can afford a downtime of 1 day but we need the data to be always available to us in latest state. I've gone through two options: 1) ...
0
votes
2answers
465 views

Large time difference between two almost identical simple queries…why?

I'm trying to understand why is there so much difference in execution time and CPU usage between two simple queries that only differ in a computation. The queries are the following: SELECT ...
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vote
2answers
6k views

How to find DELETE and UPDATE statements that have been executed on a database?

I am trying to find out what delete and update statements have been executed on a certain database in a certain period of time. I came across this following query, but it generates an error message: ...
0
votes
1answer
243 views

What is the maximum number of rows in a clustered index on datetime column?

I would like know what the max no of rows is in a clustered index (non-unique) on a datetime column table in SQL Server 2008R2.
0
votes
2answers
561 views

Using MySQL InnoDB as an Archive

My site has a main MySQL InnoDB table that it does most of its work on. New rows get inserted at a rate of 1 million per week, and rows older than a week gets moved over to an archive table on a daily ...
2
votes
2answers
827 views

Check if row exists

I need to write a query that will insert a row only once, even if the query is run multiple times. Being new to SQL (well new-ish), I did an if not exists(...) but a friend said he preferred deleting ...
0
votes
3answers
236 views

Select MaxDate where hh:mm:ss makes the difference

How to select the maximum date from a table where hh:mm:ss is selected? My query is the following, and returns the latest date, but if there are different times recorded, the date will be returned ...
6
votes
2answers
5k views

SQL Server alter table to change TEXT to NVARCHAR(MAX) greatly increasing database size

I need to update a SQL Server database thats about 18GB in size to change a significant number of TEXT columns to NVARCHAR(MAX). The problem I'm having is after executing all the alter table ...
3
votes
1answer
336 views

Creative workaround for granting edit rights to individual jobs for a group?

We have two developers that say they can not function without full rights to a few jobs on our database server. They both want rights to the same jobs. Given that it seems that MS doesn't seem to be ...
4
votes
1answer
3k views

Join To a @Table Variable is running ineficiently

Alright so I have a report sproc that was running incredibly slow. Customers were complaining that the report would not run so I started investigating exactly where in the sproc the problem was and I ...
1
vote
2answers
6k views

Need a way to query a table, and JOIN it with the TOP 1 related record from an other table

As a follow up to this question, I'm wondering if there is a better and/or more efficient way to gather the data in question. As stated, this query does return me 95% of the data I need -- SELECT ...
0
votes
3answers
989 views

Fixing a query that returns failed job information

I' using a SQL Server 2008 Sp3 environment. I have a query that returns information about failed jobs from the last 10 minutes. If a job has two schedulers (for example - a job that runs every 10 ...
2
votes
2answers
5k views

MySQL Replication without stopping master

I am currently setting up a replication for my database one of the ways i am thinking of synchronizing the master and slave without write locking the master, is by first taking a log position then ...
5
votes
1answer
2k views

How to improve performance on PostgreSQL when using multiple concurrent processes?

Seeing query performance which is not satisfactory on our Python application, which runs several processes that use SQLAlchemy core to access a PostgreSQL 9.2 database. We may have around 100 - 200 ...
1
vote
1answer
924 views

Question about Oracle's interpretation of “host cpu utilization” in v$sysmetric view

I am studying the v$sysmetric view from Oracle and trying to understand what is Oracle's interpretation of "Host CPU Utilization" It says in the metric_unit as % busy/(idle + busy), but what is busy? ...
1
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0answers
716 views

Efficiently retrieve big amount of data based on date range

Table EVENTS TimeStamp |O.Name |Location |Source | 2008-11-12 |Pretorian|Európe |England | 2009-12-24 |Lex Rosa |Európe |Italy | 2010-01-01 |Nasdaq |USA |Whasington | ...
2
votes
2answers
3k views

Only one NULL for one part of primary key

I have two date columns : "start date" and "finish date". I want to make sure that there can be only one null value in the "finish date" column (which should be current state if it's NULL) for one ...
0
votes
1answer
136 views

Implementation of stack in MySQL

I had an abstract idea of implementing a stack in MySQL. Tried a lot of Google work but couldn't reach to any logical conclusion. The Stack must be a collection of tables with the stack top pointing ...
4
votes
1answer
30k views

What queries is Oracle executing, how frequently, and time-taken?

I have a (Java) web-application, that of course executes many queries (selects, inserts, updates, deletes) to the Oracle Database. I want to find out the following for last 7 days: SQLQuery ...
1
vote
2answers
63 views

Need logic to collate data

I have a table in the below structure. phone bigint answer_time datetime I should group all phone numbers, and its total number of attempts and mention its no:of time answered and no:of time not ...
0
votes
0answers
432 views

Error in creating trigger in phpMyAdmin

I have 4 tables: event: event_id(p.k) | uid | circle_id(f.k) activity: uid | performed_activity_id(f.k->event_id) | activity_type_id follow: follower_id | circle_id(f.k) notification: sender_id ...
1
vote
1answer
69 views

Hard Parse on Non-Identical Statements?

Let's say I have this query : SELECT X FROM Y If I run it for the first time then it would do a hard parse. After that, I run this query : select x from y With just a difference in alphabetical ...
2
votes
1answer
6k views

The Cluster service failed to bring clustered service or application 'SQL Server (MSSQLSERVER)' completely online or offline

SQL Server service restarted/stopped, which cause the production database down n find this errors in System log. ERROR5:The Cluster service failed to bring clustered service or application 'SQL ...
1
vote
1answer
551 views

mysql query - how to delete duplicates based on highest int?

I'm running a reverse auction website and I need to delete the duplicate bids and keep only the highest amount . lastPriceBid_rounded is the "amount". The duplicate is defined by the userId. ...
9
votes
4answers
849 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 ...
4
votes
1answer
87 views

Index Evaluation

I have been doing some index evalaution on a table and this is the first time I have ever looked at how well indexes are performing so and would like some advice on a certain index. The non ...
3
votes
1answer
4k views

Select the top 5 records and the specific column from each table in the same database

I have 50+ tables in a database. I don't want to use the following SQL on each table in a database. select top 10 * from {table_name} So, is it possible to display the first 10 records PLUS only ...
2
votes
3answers
8k views

How to select the first 10 records for each table in the same database using sql

I have 50+ tables in a database. I don't want to use the following SQL on each table in a database. select * from {table_name} So, is it possible to display the first 10 records for each table ...
3
votes
2answers
2k views

What is the difference between using varchar(100) and varchar(255)?

I want to know difference between varchar(100) and varchar(255) in terms of memory usage and programming problems of using more memory.