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

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3
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3answers
270 views

Join table on some conditions

I've got a table called activities. And a table messages. Activity has many messages, and one message has one activity. This are the message columns : id sender_id receiver_id body activity_id I'm ...
3
votes
1answer
1k views

Is there any way to get the estimate cost of executing a query in MySQL?

In PostgreSQL, EXPLAIN or EXPLAIN ANALYZE will show the estimate cost of executing a query. But EXPLAIN in MySQL doesn't provide this information. How can I get the estimate cost without installation ...
3
votes
1answer
966 views

Distributed - across multiple databases or servers - Transactions

I have some doubts related to transactions in SQL. I perform below steps. Connection 1 open for DB1 database Begin transaction for Connection 1 Run the commands on Connection 1 Connection 2 open for ...
3
votes
1answer
1k views

Does existing msrepl_tran_version column need to be removed when re-creating replication?

What is the process for removing a replication and then re-creating the replication. I know the process to set up replication. However, If i wanted to take a publisher database copy it and restore it ...
3
votes
1answer
328 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 ...
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 ...
3
votes
2answers
12k views

ORDER BY clause is allowed over column that is not in SELECT list?

In theory, every statement in SQL Server create virtual table passed to next statement. In other words, when FROM and Where clause are finished, next step is SELECt columns from virtual group created ...
3
votes
1answer
566 views

How to categorize rows by SUM of a column in mysql?

I have a table as id num_items folder 1 4 2 33 3 74 4 41 5 24 6 34 7 46 8 55 9 11 I want to assign folder number to rows but limiting the number of items in each folder (e.g. ...
3
votes
1answer
6k views

DB2 Defining remote database alias

I'm using DB2 9.7.0.3 for AIX. I want to select data from a remote database, also running DB2 9.7.0.3 for AIX, and insert it into the local database I'm connected to. I believe the query for this ...
3
votes
2answers
9k views

GROUP BY two columns

I want to count two columns, but need to get the results of first column in one row. SELECT country, COUNT(*) FROM table1 GROUP BY country, type This query gives me country type COUNT(*) ...
3
votes
3answers
553 views

SQL JOIN Syntax in MS SQL

I have been taught in my MSSQL classes, this is how to join two tables select * from FirstTable A JOIN SecondTable B on A.ID= B.ID Now in my professional life, I came across JOIN queries like ...
3
votes
2answers
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How can I create different sets of sequential values based on another column in a table?

I've got a table that holds two types of notes. Collection Notes and Delivery Notes. They are identical data structures, hence using the same table. CREATE TABLE Notes ( Id int IDENTITY(1,1) NOT ...
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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. ...
3
votes
5answers
9k views

Copying Oracle 11g express Database from one server to another

Basically, I am a MS-SQL developer,and relatively new to Oracle. Even after great deal of research, I was unable to find any way of copying entire database from one server instance to another. In ...
3
votes
2answers
7k views

SQL Server 2008 T-SQL select hanging, but not dead locked

This is a pretty strange issue so bear with me. I have a stored proc that does some heavy duty processing. When it runs well it usually takes a few minutes depending on server load, but occasionally ...
3
votes
2answers
691 views

Transaction Log 16GB on 2MB database [duplicate]

Possible Duplicate: Why is My SQL Server Transaction Log Growing or Running out of Space? The transaction log in one of my client's databases is 16GB, when the database itself is only 2MB. ...
3
votes
2answers
4k views

Can the sorting from an ORDER BY statement be saved explicitly with only one UPDATE statement?

I have this table: SELECT * FROM items id | item | position ---|-----------|---------- 1 | USB cable | 0 2 | SD card | 4 3 | Mouse | 2 4 | Keyboard | 0 5 ...
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2answers
3k views

How do I group results in batches of consecutive rows with the same 'module'

I'm looking for a seemingly very simple SELECT. I have a logging table LOGGING of which three columns are of interest to me: MODULE (text), PDATE (date), PTEXT (text). Actually, I care only about ...
3
votes
2answers
981 views

Testing Query Speed

When I'm running a query for the first time, it takes x miliseconds to be executed. When I run it the second time it takes a lot less time. I assume that it is some caching involved in this mechanism, ...
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votes
2answers
526 views

Unique time range or database schema for a scheduling system

I'm having to design a table which contains scheduled times for media to be displayed. These scheduled times should not overlap. In my SheduledSlot table I have: id integer PRIMARY KEY begin ...
3
votes
2answers
1k views

A query submitted from different applications has differing DOP

I have a query which selects from multiple views and is fairly I/O heavy. If I execute this query using Management Studio it uses parallelism across most of the 16 CPUs and completes in under 10 ...
2
votes
2answers
60 views

Very tricky: Can't update a sequential list SQL-92 ( Filemaker)

I have a quite simple problem, but the solution is very tricky. I'm trying to solve this for months: There is a column "SortID" that needs to get updated with sequential integers, starting from 1. ...
2
votes
1answer
60 views

How to get max sequence of rows? [duplicate]

I have a table with statistic of games which has next rows (I only write about rows that has interest in this context): id BIGINT PRIMARY KEY date TIMESTAMP WITH TIME ZONE status ...
2
votes
2answers
129 views

How to get data from three different tables

This question is continuing of this issue: How to get data from two different tables? Now I need to connect the table Sessions with 2 tables: Input Downloads When I use this query with real ...
2
votes
1answer
30 views

OFFSET and LIMIT on complex query

I am doing a pretty complex query in Postgres 9.3.4: SELECT p.* FROM unnest('{19082, 19075, 20705, 18328, 19110, 24965, 18329, 27600 , 17804, 20717, 27598, 27599}'::int[]) ...
2
votes
1answer
57 views

Highest value of a row in MySQL

I searched and found many results using "Grep highest value of a row in MySQL" but I don't understand the results. I have a row which primary key value is 4 and there are another 8 values. Those are ...
2
votes
1answer
189 views

Categorize age ranges and display in one column

I want to see the data as follows Member Age Category Test1 25 Under 30 Test2 55 51-60 Test3 67 Above 60 I have used the below query (from an answer to my previous question) to ...
2
votes
1answer
249 views

Row with latest timestamp

How to get the row with the latest value in a TIMESTAMPZ column? Is an index needed? Does an index change the strategy? Would behavior vary by database (I'm using Postgres 9.4)? My app records data ...
2
votes
2answers
387 views

Repeating rows of date intervals based on another table in Oracle

I have a table of maintenance plans with date intervals between each required maintenance period. Fiddle: http://sqlfiddle.com/#!4/af742 create table maint_sched (maint_id number, start_date date, ...
2
votes
1answer
601 views

Keep Execution Plan in Cache - SQL Server 2012

How can I keep a query execution plan in SQL Server's cache and use it several times? When I execute a query for the first time it takes 7 seconds. After that it takes only 1 second. This query is ...
2
votes
2answers
227 views

Is unique index better than unique constraint when an index with an operator class is required

Postgres docs say: The use of indexes to enforce unique constraints could be considered an implementation detail that should not be accessed directly. One should, however, be aware that there's ...
2
votes
3answers
1k views

find all numbers that appear at least three times consecutively

This is a question from leetcode online judge I tried this SELECT Num FROM Logs GROUP BY Num HAVING COUNT (Num) >1 but got runtime error!! Anyhelp would be appreciated
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1answer
2k views

Alter table Statement Failed -Msg 207, Level 16, State 1

I wrote a script to add a column in a table and on successful execution update its values. I know it’s just a simple script but what is wrong with the ‘IF NOT EXISTS’ statement why script between ...
2
votes
3answers
3k views

Return total number of rows and selected (aggregated) data

I have a function which is selecting some data from a table. I would like to return the selected data and the total number of rows in that table. How can I do that or how can I get the same result in ...
2
votes
1answer
555 views

Difference data between adjacent rows

I have a table (called Visits) with ReqTime DATETIME NOT NULL column AND Duration INT UNSIGNED column. Duration should be set to the difference of ReqTime for two adjacent rows. But Duration is not ...
2
votes
2answers
210 views

Database events that will cause deletion of index

In SQL server if we try to change a data type of a column having index ,then it deletes the indexes associated with that column and changes the data type . I was not aware of it and was faced problem ...
2
votes
2answers
9k views

How do I include nulls during comparisons in SQL Server?

So basically in SQL Server a NULL means there is no value and thus can't be compared which returns some unexpected results. For example, the following query doesn't return rows where value IS NULL ...
2
votes
4answers
1k views

How to join the latest previous record with SQL

The original question was posted on stackoverflow. I think this site could be more focused on db related topic. I have a table whose schema is like this: CREATE TABLE product_shipping( ...
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votes
4answers
10k views

Is it ok to change from full recovery to simple recovery in Sql Server

I have an old database - a users membership/role that was setup automatically by an ASP.Net 2 application years ago: The Sql Server version currently running is: Sql Server 10.5.1617 The users ...
2
votes
0answers
77 views

Modulus calculation for compound primary keys in MySQL Cluster (and other sharded databases)

In MySQL Cluster, and generally in sharded databases, how is a compound primary key's modulus calculated? Say, for example, there are two tables that have primary keys like so: CREATE TABLE Orders ...
2
votes
2answers
275 views

Design of an application log database

We are generating logs like following example(this is a table no actual pipes): 2014-06-10 09:00:03.457 | Channel1 | Operation3 | Function15 | 15ms 2014-06-10 09:00:08.245 | Channel2 | Operation5 | ...
2
votes
2answers
443 views

Count where previous record exists in either of two tables

I'm trying to COUNT records on one table where both the counted records and their "previous" records exist either in the same table or on another. The table that I'm sampling has a composite PRIMARY ...
2
votes
1answer
558 views

How to speed up looped INSERT INTO statements?

I currently use the following statement, for 10,000 rows it takes about 150 seconds. I tried removing the index on the target table, but this didn't help. Running the loop without the INSERT INTO ...
2
votes
2answers
8k views

Possibly tempdb out of space or a system table is inconsistent

While running DBCC CHECKDB I got this error Msg 8921, Level 16, State 1, Line 1 Check terminated. A failure was detected while collecting facts. Possibly tempdb out of space or a system ...
2
votes
2answers
199 views

How to merge column in mysql depending on match

I have one table which looks like this in mysql column1 column2 name column3 data 1 1 foo 1 1.5 1 1 foo 2 2.5 1 1 foo 3 ...
2
votes
2answers
107 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 ...
2
votes
2answers
419 views

UPDATE table with another table data

I want to update the table car_check field fencing.(total 40 rows).I also use postgis function. I think it's a little difficult.Any suggestions? The code is the first carid example. UPDATE car_check ...
2
votes
2answers
347 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) ...
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2answers
3k views

Optimizing removal of duplicate rows from recursive CTE query

I need to write a recursive SQL query to fetch multiple projects together with their lineage from the following table: CREATE TABLE #Project ( Name VARCHAR(10), ParentName VARCHAR(10) ) INSERT INTO ...
2
votes
1answer
792 views

counter table in mysql

i was going through the book: High performance MySql 2nd edition. In chapter 4 it says: An application that keeps counts in a table can run into concurrency problems when updating the counters. ...