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

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9
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1answer
2k views

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 ...
20
votes
3answers
11k views

What is the best way to get a random ordering?

I have a query where I want the resulting records to be ordered randomly. It uses a clustered index, so if I do not include an order by it will likely return records in the order of that index. How ...
0
votes
1answer
352 views

Improve Insert performance for 200 Million rows

How can the following insert statement be improved - which varies from 20mins on certain days to 70-140mins on most other days. SELECT DISTINCT od.SourceID, od.OrderID, od.OrderLineNo, ...
1
vote
1answer
334 views

complex update query postgres

I've got a bunch of ids from table messages and I want to update the table activities. This is how I imagined my query would work (so you get better idea what I'm trying to accomplish): update ...
1
vote
1answer
211 views

Can I rely on this SQL shortcut to save a query?

Consider a table with a status field that holds one of two values: | status | set('active','default') | YES | | active | I need to know how many records are in the table, and additionally how ...
2
votes
1answer
506 views

DB2 SUM / INNER JOIN question

I have a query that is the following: SELECT CMSTKY AS Customer, CMNAME AS BusinessName, WKMDL# As Model WKSLD# AS Sales FROM GPCMP INNER JOIN GPCM1P ON GPCMP.CMSTKY = ...
0
votes
0answers
313 views

Postgres vs MySQL Database Maintenance

I have been using Postgres and MySQL for a long time now. There are a few routine maintenance chores that must be performed on a regular basis to keep a PostgreSQL server running smoothly. As as ...
0
votes
1answer
752 views

rownum won't return records above 100

I have this query: SELECT * FROM ( SELECT v.*, ROWNUM recnum FROM ( SELECT hostaddress, modulename, severity, escalation, classification, ...
5
votes
1answer
233 views

Why are zero length spaces being returned from a Union All against an empty table in SQL Server 2005 but not SQL Server 2012

Supporting an existing VB6 app with a SQL Server 2005 back end and we're migrating our database server to SQL Server 2012. Created a backup of the production database and restored it into a dev ...
0
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0answers
181 views

How can I number my groups using an Access “Find Duplicates” Query?

I have a query created by the MS Access 2010 find duplicates wizard. It is: SELECT * FROM fbExpenses WHERE [expense_date] In (SELECT [expense_date] FROM [fbExpenses] As ...
2
votes
2answers
146 views

SQL Server - Recursive “find all FK connections for ID through the entire DB” query

I'm dealing with a DB with hundreds of tables, with interconnecting FK references producing potentially thousands of different permutations for how for example table A and table K can join together. ...
0
votes
1answer
60 views

Check whether MySQL Innodb Rows are compressed

After setting the various variables to enable compression on the Innodb Barracuda tables, what query will you use to check that those tables are indeed compressed?
-1
votes
1answer
246 views

MS Access + MS SQL Server for 1160+ users - Is it worth it? (Please Help!) [duplicate]

Our school in Delhi (India) wants to develop a professional and robust in-house database (SIS) that should handle vast amount of student information, including admissions, registration, re-enrollment, ...
8
votes
3answers
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 ...
2
votes
2answers
70 views

Table Transformation with SQL?

I got a set of tables which have been imported into a database by transforming them like shown in the following picture: Now it is necessary to get the former tables back. Unfortunately the guy who ...
8
votes
2answers
2k 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 ...
0
votes
2answers
85 views

MySQL foreign key error

I need to update rows in a child table,but I am getting following error while I run the code, Company Table CREATE TABLE `company` ( `Company_id` int(11) NOT NULL AUTO_INCREMENT, `Company_name` ...
-3
votes
2answers
2k views

How to calculate the hours worked by all employees in a day? [closed]

vinay_hours id cico 1 2014-02-20 10:31:00.503 1 2014-02-20 13:00:00.503 1 2014-02-20 15:31:02.503 1 2014-02-20 19:00:02.503 2 2014-02-20 10:00:02.503 2 2014-02-20 18:31:02.503 expected ...
0
votes
0answers
82 views

query comes in slow query when log_queries_not_using_indexes is enabled

This query comes in slow query log when log_queries_not_using_indexes is enabled. SELECT a.id, d.id AS city_id, d.city FROM booking a, sub_area_master b, area_master c, city_master d WHERE ...
2
votes
2answers
84 views

Nearest value for each foreign key

I have a table with a primary key, timestamp, value, foreign key. I would like to find the nearest value to a timestamp for each of the foreign keys in a list. Unfortunately, the gap from the given ...
-2
votes
1answer
51 views

Is it completely pointless to use NOT NULL after DATE types? [closed]

From my current knowledge and experience, it is not possible to insert NULL into a DATE type, so what would be the point in declaring NOT NULL at table creation? I see this quite often throughout ...
0
votes
1answer
206 views

Is there a more efficient way of using a match score in MySQL full text search?

SELECT i.*, MATCH(i.description, i.keywords) AGAINST ("searchterm") AS score FROM items AS i WHERE i.instock=1 AND MATCH(i.description, i.keywords) AGAINST("searchterm") ...
3
votes
1answer
261 views

Postgresql query slowed with table growth

I have a very simple table in Postgresql, and need some guidance to speed up my queries. Recent large expansion of the data in the table has made everything grind to halt. Table body_feature: ...
1
vote
2answers
1k views

Get row from table for last date before date parameter if no row for date parameter or entries null

I have table, which holds the exchange rates for currencies. There is also a Date column, which holds the currency exchange rates acquisition date. For some dates there is a row, but no currency ...
2
votes
1answer
52 views

Generate Backup list

I have the query below that returns all databases and full backup history with the last backup date and device name. I am trying to modify the query to only return all the databases and just the last ...
-1
votes
1answer
57 views

How to compare a result of a query to a number? [closed]

I have a query that return selects a table and returns one column with a number, and I want to know if the result is > 0. SELECT * FROM Table WHERE (SELECT amount from Table2) > 0 ...
1
vote
2answers
2k views

Improve performance with the WHERE NOT IN sub-select clause

In the following query, I have to count transactions for each customer. [EDIT]However, I have to exclude from the result set entirely, customers that have a transaction older than one year. ...
2
votes
0answers
64 views

Setting up triggers based on exposed columns in a view's source table

I have a table where I want to do a AFTER UPDATE trigger if one of the columns modified was in a specific view CREATE VIEW [dbo].[iv_EmployeesView] AS SELECT EMPLOYEE_GUID AS EmployeeGuid, ...
1
vote
1answer
8k views

mysql trigger to insert/update date column from datetime column

probably simple question but can't get it to work: I have a table with two datetime columns. In order to set up a date index and have simpler queries, i have added two date columns next to them. ...
1
vote
2answers
68 views

SQL Select query with postgresql

I'd like to find all rows if is shows even once a particular value with postgresql For example : id TIT_CODE CLI_NOM CLI_PRENOM CLI_ENSEIGNE 1 M. DUPONT Alain A 2 M. ...
-2
votes
1answer
676 views

How to prevent duplicated records when applying ORDER BY NEWID() to fetch them randomly? [closed]

I tried using the solution provided in http://stackoverflow.com/questions/1117761/sql-query-to-return-rows-in-random-order to fetch random records in my query. But I have to add NEWID() to the list of ...
2
votes
2answers
267 views

Order of returned record with IN statement postgres

I know that the order of returned records is not guaranteed with the IN statement for Pstgres. For example if I do this: SELECT "users"."id" FROM "users" WHERE "users"."id" IN (13589, 16674, 13588) ...
0
votes
0answers
13 views

MySQL: Updating a column referenced by two foreign keys in the same table leads to foreign key constraint failure [duplicate]

MySQL 5.5 I have a simple InnoDB table: CREATE TABLE `T` ( `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT, `deleted` bigint(20) unsigned NOT NULL DEFAULT '0', `other` varchar(32) DEFAULT ...
10
votes
3answers
3k views

Database starts always in recovery mode

Everytime I restart my server, the database is always in recovery mode, and it takes about 20 minutes for it to behave as normal. This always and only happens when I restart the server, so I have a ...
0
votes
1answer
778 views

importing database backup to phpmyadmin return #1064

When I tried importing mysql database backup to MySQL using phpMyAdmin I got the following error message: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your ...
3
votes
1answer
12k views

Cassandra - Query a column with collection type

I am pretty new to cassandra, so pardon me if this turns out to be a silly question. I have a table structure as below CREATE TABLE data_points ( id text PRIMARY KEY, created_at timestamp, ...
0
votes
1answer
39 views

Select permission to each table

I have three schemas Production, HRecourse and Sales,tables in every week create and drop , I have six Users P_User1, P_User2, HR_User1, HR_User2 and S_User1 and S_User2. I have to grant then how i ...
1
vote
0answers
228 views

Combine a running balance SQL statement as a column

I have two Select Statements which are collecting data from 1 table, one is a totals select statement. Could anyone assist me with combining them into 1 statement? Any assistance is appreciated ...
0
votes
2answers
980 views

Select * on inner join with common columns

I have 3 tables (mysql db) on which I want to do an inner join. The problem is that these tables have common columns. I know I could use aliases to differentiate them (select A.x as Ax, B.x as Bx, C.c ...
0
votes
0answers
51 views

postgres database program to save sql templates and search where used it

I have a postgres database with tables and functions build using sql templates. And I would like to use a database program to save these templates and search where I used it. What i want to do is to ...
1
vote
1answer
174 views

Optimizing Postgres query

I've got a one to one relation from users to addresses table. Where one user can have one search address and one verified address. I've got two indexes on addresses table : Index on state field ...
0
votes
1answer
602 views

Executing a SQL Job only once a month and after completion of a specific job

Let me better explain. My first job executes every 15 minutes (top of the hour, 12:15, 12:30 and 12:45). It does this for every day of the week. I have a second job that runs at 1:30 AM on the first ...
2
votes
0answers
284 views

SQL Server 2012 Database Engine Configuration Storage type Raid [closed]

I just inherited a Server that I have to rebuild for SQL Server 2012, I was wondering what would be the best disk configuration for the database engine. This is what I have: 6 x 300GB 10k: 2 x 1TB ...
3
votes
2answers
1k views

View scripts ran by a specific user?

I read in a stackoverflow post that you can restore scripts from the past 24 hours by using this query: Use <database> SELECT execquery.last_execution_time AS [Date Time], execsql.text AS ...
2
votes
1answer
66 views

Selecting distinct records

I have a user relation to address (1 to 1). So the address has two types which is a type column. One is the VerifiedAddress and the other one is the SearchAddress. So the user who had verified his ...
0
votes
1answer
208 views

Can't get rid of “temporary; Using filesort”

I can't get rid-off "temporary; Using filesort" when ordering columns from the second table explain SELECT * FROM post JOIN post_plus ON post_plus.news_id = post.id ...
0
votes
1answer
253 views

What is the correct name and significance of EAV table pivot?

I've been forced to use a very uncomfortable structure for a table. After trying to up similar examples, I've discovered the EAV, which seems almost like a pivot of said structure. The attribute order ...
0
votes
2answers
331 views

Separating a date column in Access into Month, Day and Year while keeping the new columns ordered by a seperate column(primary key)

I have a column titled DateOpen which lists the date files were opened in d/m/yyyy format. I want to split the entries in that column into new columns titled MonthOpen, DayOpen and YearOpen while ...
2
votes
1answer
109 views

Understanding postgres reason for picking this query plan

I ran a query: select * from orderline where orderid = 12345 and status > 0 that gave me the following plan: Bitmap Heap Scan on orderline (cost=286370.00..531410.78 rows=76372 width=155) ...
1
vote
1answer
138 views

Create database before restore multiple files

I've several database, most of them have multiple files (both data and logs) and multiple diff and trn backups. I've already a restore script (scheduled and working on other server) that takes all the ...