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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1
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1answer
272 views

Optimistic Paging and separate query for COUNT?

I am using SQL SERVER 2012 FETCH/OFFSET after searching a lot that this will give me the best performance. But for paging to work, I need a Total count. There are 2 ways to achieve this. 1) Paging ...
1
vote
2answers
966 views

Unnest multiple arrays into rows

I have been shown a great way to bulkinsert with this example: WITH p AS ( INSERT INTO parent_table (column_1) SELECT $1 RETURNING id) INSERT INTO child_table (parent_table_id, ...
1
vote
1answer
70 views

Oracle - Date of Selection on table

how to get last date when someone perform selection on table? Last accessed in terms of select statement only not last updated date
1
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4answers
132 views

Backup from Server1 and restore it to Server2?

IF we have two Servers installed with SQL Server 2008 instances, Server1 has three drives C, D and E with 100, 500 and 500 GB respectively and Server2 has three drives C, D and E with 100, 300 and ...
1
vote
1answer
147 views

Get maximum number with combination of columns [closed]

I have table with columns like AutoID, Number, Name, City, State, Country. What I wanted is the maximum number entered in the “Number” column with the combination of Name, City, State and Country. ...
1
vote
3answers
163 views

Creating a copy of primary database and attaching the copy database in the same sql instance

I just got into a project in which we have only one SQL Server 2012 copy. We have 12 databases attached to the primary instance of SQL Server 2012. As I don't have SQL Server 2012 or supporting OS, I ...
1
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3answers
3k views

SQL services wont start due to incorrect drive letter after windows restore

SQL services wont start due to incorrect drive letter after windows restore Had a server crash, was successfully able to reinstall windows and restore the server SQL and all the necessary services ...
0
votes
2answers
73 views

Counting unique records across 2 columns and computing a score based on boolean values

I have a table that looks like this in Google Big Query: custID InteractionDate Purchased? Sales 1 20150312 F 0 1 20150312 T 200 1 20150314 ...
0
votes
0answers
50 views

Auditing SQL Server 2012 [closed]

I work for the State of California. I am working on a project setting up a Data Warehouse sharing data between 3 state agencies. The Data Warehouse will be encrypted. I would like to know what are the ...
0
votes
2answers
49 views

MySQL Case problem

I am trying to run a SQL code (I use MySQL). What I want to do is to set DATE_REACT a value when the first condition is satisfied, and a different value when the first condition is not satisfied. The ...
0
votes
1answer
141 views

Splitting Columns

I want to ask a complicated question and I think its advanced a little. I have a table has this design, its an attendance system. I need to split the time if the attendance count per day was not 2: ...
0
votes
1answer
353 views

How do I count the number of different child id's belonging to a parent record?

For instance I have two tables in a music database. Table album and table track. Each track record has (amongst other things), an album_id and an artist_id Each album record has a unique album_id ...
0
votes
2answers
121 views

Which should I use on my DB? - Clustered Index or Non Clustered Index or Both

I just need advice on how I am going to optimize my database. Date ---- Time ---- Area ---- Block ---- Data1 ---- Data2 ---- Data3 ---- DataN I have that format of tables on my database. Each ...
0
votes
1answer
257 views

How to rollback last executed sql script fired as sysdba

I have fired one sql script as sysdba which I have to fire using other oracle user. I have already created some user and each application running on each oracle user. By mistake I had fired a script ...
0
votes
3answers
5k 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 ...
-1
votes
1answer
481 views

The SQL server Log folder is expanding because of the SQL Dump files (what to do with it ?)

The "Log" folder SIZE in the SQL server root directory (X:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Log) becomes too big , ~80 GB. When I checked it, I see that there are a lot of ...
-1
votes
1answer
197 views

Validate each parent intermediary is also a parent to itself

I want to validate where each parent intermediary is also a parent to itself. So this query should return invalid parents in SELECT if table has any. I need to do is first of all get all parents ...
-5
votes
1answer
8k views

how to query multiple row data in single column in oracle?

i have a table in which the values are id value ---------------- 1 10 1 20 1 30 2 33 2 34 I want the output given below using sql: id value ...
76
votes
7answers
14k views

Where are some useful SQL puzzles to teach SQL in a workplace?

I'm looking for beginner and intermediate level SQL puzzles, that I can point trainees at for practice. I'm aware of http://sqlzoo.net/ which is a great resource - is there anything else out there ...
18
votes
11answers
52k views

Eliminate duplicates in ListAgg (Oracle)

Prior to Oracle 11.2 I was using a custom aggregate function to concatenate a column into a row. 11.2 Added the LISTAGG function, so I am trying to use that instead. My problem is that I need to ...
24
votes
2answers
11k views

Is it a bad practice to always create a transaction?

Is it a bad practice to always create a transaction? For example, it is a good practice to create a transaction for nothing but one simple SELECT? What is the cost of creating a transaction when it ...
22
votes
4answers
7k 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 ...
16
votes
5answers
76k views

How to select the first row of each group?

I have a table like this: ID | Val | Kind ---------------------- 1 | 1337 | 2 2 | 1337 | 1 3 | 3 | 4 4 | 3 | 4 I want to make a SELECT that will return just the ...
24
votes
3answers
41k views

How do I use currval() in PostgreSQL to get the last inserted id?

I have a table: CREATE TABLE names (id serial, name varchar(20)) I want the "last inserted id" from that table, without using RETURNING id on insert. There seem to be a function CURRVAL(), but I ...
13
votes
3answers
13k views

When a previously-fast SQL query starts running slow, where do I look to find the source of the issue?

Background I have a query running against SQL Server 2008 R2 that joins and/or left-joins about 12 different "tables". The database is fairly large with many tables over 50 million rows and about 300 ...
13
votes
5answers
12k views

Alter table on live production databases

How do most "popular" (MySQL, Postgres...) database system handle altering tables on live production databases (like adding, deleting or changing the type of colums)? I know the correct way is to ...
12
votes
2answers
2k views

Why are simple SELECTs on InnoDB 100x slower than on MyISAM?

I have quite an annoying problem. I want to use INNODB as my main database engine and give up on MyISAM as I need the former for using galera-cluster for redundancy. I copied (description follows) ...
11
votes
3answers
7k views

How to differentiate between SQL and PL/SQL?

I know the question might sound too stupid, but I never understood this part. SQL*Plus works with both SQL and PL/SQL. How do I know whether some code is SQL or PL/SQL? If my code has a for ...
10
votes
2answers
37k views

Returning a result set with multiple rows based on max date

I have a child table that is something like this: [Cust Date Table] | Customer ID | Some Date | Balance | +-------------+------------+---------+ | 1 | 2012-04-30 | 20.00 | | 1 ...
9
votes
3answers
5k views

CHECKPOINT or COMMIT writes to disk?

Let's say, for SQLServer2008R2 and higher, with full recovery mode databases. I always thought : When a transaction is commited (COMMIT), the transaction is written to the transaction log in RAM. ...
27
votes
8answers
26k views

What is the difference between an INNER JOIN and an OUTER JOIN ?

I am new to SQL and wanted to know what is the difference between those two JOIN types? SELECT * FROM user u INNER JOIN telephone t ON t.user_id = u.id SELECT * FROM user u LEFT OUTER JOIN ...
25
votes
3answers
13k views

How to execute SQL against all DBs on a Server

I have some standard SQL that I run against multiple databases on a single server to help me diagnose problems: select so.name, so.type, MAX(case when sc.text like '%remote%' then '' ...
8
votes
3answers
3k views

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 ...
7
votes
4answers
60k views

Combine column from multiple rows into single row

I've got some customer_comments split out into multiple rows due to database design, and for a report I need to combine the comments from each unique id into one row. I previously tried something ...
7
votes
2answers
6k views

Database behind a Multilingual User Interface

This question is about an issue somewhat more complicated than the one which has already been addressed in these old questions, all of which are duplicates of one another: Suggestion for database ...
10
votes
1answer
2k views

Generate an exception with a Context

When PostgreSQL throws an exception, there is a line "CONTEXT" like: ERROR: INSERT has more target COLUMNS than expressions LINE 3: ... ...
2
votes
2answers
3k 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 ...
19
votes
5answers
9k views

How do I copy a table with SELECT INTO but ignore the IDENTITY property?

I have a table with identity column say: create table with_id ( id int identity(1,1), val varchar(30) ); It's well known, that this select * into copy_from_with_id_1 from with_id; results in ...
11
votes
2answers
992 views

Optimization: Moving variable declarations to the top of your procedure

While working on optimizing some stored procedures, I sat down with the DBA and went through some sprocs with high blocking and/or high read/write activity. One thing the DBA mentioned was I should ...
9
votes
3answers
10k views

Are individual queries faster than joins?

Conceptual question: Are individual queries faster than joins, or: Should I try to squeeze every info I want on the client side into one SELECT statement or just use as many as seems convenient? ...
7
votes
2answers
7k views

Why does MySQL allow HAVING to use SELECT aliases?

In SQL, as far as I know, the logical query processing order, which is the conceptual interpretation order, starts with FROM in the following way: FROM WHERE GROUP BY HAVING SELECT ORDER BY ...
5
votes
5answers
8k views

Emulate REGEXP like behaviour in DB2 SQL

I posted the same on stackoverflow (please, let me know if I have to delete one). I'm working on a DB2 database and as far as I can see regexp is not supported (without additional libraries). So I ...
4
votes
2answers
568 views

Open source and commercial tools to build dynamic queries of fact tables in star schema [closed]

What user interfaces or tools (commercial and/or open source) can query a star schema model (Ralph Kimball dimensional model)? So for example, if we have X fact tables, and Y dimension tables, and Z ...
16
votes
2answers
49k views

Sql Server database in recovery: How to stop, Take ofline or delete?

I have a development database which has entered recovery mode on restart, and has been recovering for the last hour or so. I need to either stop the recovery, or kill it in some way. I dont care one ...
16
votes
4answers
1k views

Is table aliasing a bad practice?

I remember learning to do this in a DBMS course for Master of Information Services students. To save yourself some typing, you can type: SELECT t1.id, t2.stuff FROM someTable t1 ...
13
votes
2answers
10k views

MySQL and window functions

It seems that MySQL does not support window functions. E.g. the simple: COUNT(*) OVER() AS cnt does not work. What I am not sure is if this applies to commercial version as well (I assume the ...
11
votes
3answers
504 views

Can IS DISTINCT FROM be combined with ANY or ALL somehow?

Is a postgres way of combining IS DISTINCT FROM with ANY or some other neat way of getting the same result? select count(*) from (select 'A' foo union all select 'Z' union all select null) z where ...
8
votes
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 ...
8
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 ...
7
votes
2answers
23k views

Connect to SQL Server with Windows Authentication in a different domain

I am trying to connect to a remote SQL Server on a VPN in a different domain. When I enter the Server name on the SQL Server and choose Additional Connection Parameters to add some extra stuff needed ...