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

learn more… | top users | synonyms (1)

1
vote
4answers
81 views

PostgreSQL execute a default query when no row are returned

I need to calculate the average score of a list of userId. I have a table user_place_score: (user_id, place_id, score) Sometimes I do not have the score (no row for (user_id,place_id) in the ...
1
vote
2answers
356 views

Deleting duplicate rows with condition(Using SQL and LINQ)

I have a table with 5 columnsID,CPT4,CPT4Mod,ItemCharge,Eff_Date. Deletion Condition: When rows exists with duplicate CPT4and CPT4Mod field values but different ItemCharge and Eff_Date values, ...
1
vote
2answers
96 views

Convert date and time

I have a column with about 100 records in datetime (for example 2004-08-09 12:20:41:000) and I would like to convert all records or update same time just date only with format mm-dd-yyyy. Thank you. ...
1
vote
2answers
74 views

Making a Database Online [closed]

I am so confused with this issue, I have vb.net application and it has a sql database . Now, I want this application to access the sql server from anywhere , because there are many clients sharing ...
1
vote
1answer
12k views

Oracle XE 11g (ORA-12514: TNS:listener does not currently know of service requested in connect descriptor )

I have already seen the questioned in the stack overflow that might relate to my problem but let me emphasize that none of them could resolve my issue. issue is: when I wanted to integrate OWASP ...
1
vote
1answer
365 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
2k 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
76 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
vote
4answers
208 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
198 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
195 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
vote
3answers
7k 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
vote
3answers
4k 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 ...
1
vote
3answers
5k views

How do I use SSMS to compare Database 1 Table 1 against Database 2 Table 1?

I have two database - Database1 and Database2. Both database contain a table that have similar structure as follows: ...
1
vote
3answers
10k views

How to import Sybase .db file into SQL Server database?

I've been given a Sybase .db file by a client and I need to import that into a new SQL Server database so that I may see the data as well as the tables and their relationships, any ideas on how that ...
0
votes
2answers
154 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
66 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
55 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
168 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
541 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
1answer
4k views

pivot a table with cell name as column name

I have a table structure is : year | code | name| value | wef | 2014 | a001 | abe | 2000 | 2014-04-01 | 2014 | a001 | def | 3000 | 2014-05-01 | 2014 | a002 | abe | 2000 | 2014-06-01 | ...
0
votes
2answers
152 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
327 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 ...
-1
votes
2answers
43 views

how to Create A SP with table variable and execute 3 SP statements in the same statement

how to Create A SP with table variable and execute 3 SP statements in the same statement . exec [dbo].[sp_KPI_Churn_MTD_Current_Year] exec [dbo].[sp_KPI_Churn_MTD_Previous_Year] exec ...
-1
votes
1answer
2k 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
198 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 ...
-4
votes
1answer
45 views

Why all ranking is 1 for this query [closed]

Declare @ranking_term char set @ranking_term ='Amount' select case (@ranking_term)when'Amount' then ( select Dense_rank() over (order by Amount desc) ) else( select ...
-6
votes
1answer
10k 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 ...
82
votes
8answers
18k 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 ...
26
votes
13answers
69k 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 ...
10
votes
3answers
10k 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. ...
28
votes
5answers
55k 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 ...
15
votes
3answers
6k 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) ...
14
votes
4answers
27k 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 ...
23
votes
1answer
8k views

Postgres UPDATE … LIMIT 1

I have a Postgres database which contains details on clusters of servers, such as server status ('active', 'standby' etc). Active servers at any time may need to fail over to a standby, and I don't ...
15
votes
5answers
18k 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 ...
14
votes
5answers
3k views

How to recursively find gaps where 90 days passed, between rows

This is a kind of trivial task in my C# homeworld, but I don't yet make it in SQL and would prefer to solve it set-based (without cursors). A resultset should come from a query like this. SELECT ...
13
votes
3answers
10k 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
44k 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 ...
20
votes
1answer
21k views

Difference between Hash, Merge and Loop join?

In SQL Server you can specify the join hints: HASH JOIN MERGE JOIN LOOP JOIN What is the definition of those three join hints, and when should each be used?
16
votes
4answers
17k 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? ...
9
votes
3answers
6k 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 ...
8
votes
2answers
8k 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 ...
32
votes
3answers
36k views

N prefix before string in Transact-SQL query

Would you tell me, please, when should I use N prefix before string in Transact-SQL query? I have started to work with a database where I don't get any results using query like this SELECT * FROM ...
27
votes
1answer
52k views

How to force drop database in SQL Server 2008

I'm trying to force drop a database, but after dropping the database, when I try to recreate the database, I'm getting the error cannot create file C:\Program Files.....[databasename].mdf because ...
27
votes
3answers
18k 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 '' ...
16
votes
2answers
44k 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 ...
11
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: ... ...
8
votes
2answers
9k 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 ...
7
votes
4answers
70k 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 ...