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

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How to add SQL Server in networks list?

After changing my PC name and workgroup, I am no longer able to connect to SQL Server. Currently in my servers list I have only Home & localhost. Anybody know how to add server to networks list? ...
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4answers
21k views

Recursive self joins

I have a comments table, which can be simplified down to this: comments ======= id user_id text parent_id where parent_id is nullable, but might be a key for its parent comment. Now, how can I ...
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2answers
203 views

sp_publication_validation procedure doesn't seem to work properly

I am trying to use sp_publication_validation stored procedure to validate that my replication setup is working correctly. This procedure is pretty straightforward and is described here. I am running ...
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3answers
927 views

Can set unique constraint in table have data not unique SQL Server? [duplicate]

I have a table with has many rows, I want to set unique constraint for this table, but the column that must be unique, has data is not unique. Is any way to set unique constraint for this table for ...
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2answers
1k views

My database is missing and disappeared after detaching it

I have detached my database from SQL Server 2008 and unfortunately I do not know its path and by my connection string I extract its exact name and searched it but it is disappeared from my computer. ...
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1answer
119 views

Row-level subquery caching?

I have a query that uses a CTE which contains millions of rows. I plan to call this query many times, and the CTE returned each time will have most of the same rows. Is it possible for me to cache the ...
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1answer
42 views

Index on integer column not helping. Help? (EXPLAIN ANALYZE output inside)

The table market_trades has an integer column market_id which takes values from 1 to 5. This seems like a pretty straightforward query to get the number of trades on each market: WITH markets AS ( ...
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1answer
58 views

Optimizing a query on a large table (EXPLAIN ANALYZE result inside)

I have a table market_trades with a timestamp column: api_production=# \d market_trades; Table "public.market_trades" Column | Type ...
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28 views

Combining 2queries: One filtered Users on Role, One Select users with only one specific role

First query: Selects All users with specific rid ( 3 or 4 or 19 or ...). SELECT u.uid AS uid, u.name AS name, fn.field_full_name_value AS field_full_name_value FROM users u LEFT OUTER ...
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440 views

How to handle many columns / variable schema?

I apologize in advance in case this question has been asked already. I'm working on revamping a reporting application used within my company. The requirements are: Support addition of new fields ...
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1answer
285 views

PostgreSQL SQL syntax - JOIN and substrings

I have a single table of hostnames and NFS exports, some but not all of which are related. Example entries: HOST VOLUME ----- ---------- host1 vol1 host1 vol2 host1 ...
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1answer
690 views

Beginner questions about SQL and relational algebra

I'm doing some exercices waiting for the exam. I have some doubt. RELATIONAL ALGEBRA These are the table: Newspaper (Cod_n, Name_n, Publisher) Article (Cod_a, Title, Topic, ...
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13 views

How to back out of mass update in SQL Replication [duplicate]

We have a database which is set up in Merge Replication. We accidentally updated hundreds of thousands of records in a large published table on the publisher database. We did is something like ...
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1answer
104 views

Determining what query was called

I want to reverse engineer what exactly happens to the MySQL database when a product is added in Magento. I will have to reproduce the query, because I would like to manually enter new records using a ...
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4answers
50 views

where clause: if this value from col x make sure col y is this value

I feel like this is an easy one for you Experts! I haven't done any kind of Advanced SQL in years. Fundamental question: select * from myTable where ((if col1 = 'this', make sure col2 = ...
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3answers
3k views

Delete all the data from all tables

I have a little problem. I have to delete all the data from our database. I don't want to drop tables, only delete the data sets. These are 47 tables in total. I tried the following: Delete ...
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5answers
466 views

Find all values not present for other values of other column

Let's suppose I have a table with integer columns a and b (each pair (a,b) is unique) and following data: a | b ------- 1 | 2 1 | 3 1 | 4 1 | 5 2 | 1 2 | 3 2 | 4 3 | 1 3 | 3 Now I need to ...
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1answer
160 views

Joining timestamped records with the most-recent-prior records from another timestamped table

Say I have 2 tables: Table: sales timestamp timestamp without time zone amount numeric Table: prices timestamp timestamp without time zone price numeric How can I get a ...
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0answers
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How to append records from one complete table into a partly populated differently formatted table?

I have two tables of interest linked in a MS Access 2007 database. The master table called EMPL_MASTER (from which I only have read access, I cannot make changes) updates every time a system ...
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1answer
37 views

how to optimize grouped select from an already grouped select query

I already had a specific query to get a number of shops, but I couldn't sum the cost field, I kept on getting an error on the sum function, but it worked when I did this; select tab.shop_id, ...
2
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1answer
135 views

Foreign key, key split in two tables

I have to record a list of events made of action, reason (optional, may be multiple), user. I have a master table with all the valid action, and another with all the valid action-reason combination. ...
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votes
1answer
521 views

Bad Design or Complicated Query?

Problem: For fun I am building a Database for lottery results to get some statistics off of. As of now I am only interested in a Pick 3 style lotto and might introduce more later. How would you ...
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1answer
542 views

PL/SQL group orders by date and sum the total [closed]

I need to group orders by date and sum the total, My table looks like this : TEST_DATE TEST_ID - NUMBER SUCC_ID - NUMBER I need to group by date and sum the total, this is my query: SELECT ...
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1answer
102 views

Is there any performance difference between a group by statement and nested select statements in sql?

I am curious to know about the differences between using group by statement and nested selects to achieve the same result. for example consider I have two tables such as the following: tblPurchase ...
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1answer
45 views

Count(*) as rolecount, filter by rolecount = 1

How can i filter out the rows who only got rolecount = 1? WHERE rolecount = 1 gives an error. Can't really figure out how to do it. SELECT u.uid AS uid, u.name AS name, u.picture AS picture, ...
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1answer
489 views

PostgreSQL 9.3 - Performance Issue: Counting table entries slower with jdbc postgres driver

I'm using PostgreSQL 9.3 and want to ask if it is possible to improve the performance of my queries based on the following database schema: CREATE TABLE "entities" ( "id" BIGSERIAL, "type" INT ...
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2answers
46 views

assign selected columns to a variable

Select sum(column_a) as a, sum(column_b) as b round(a / b) From table Group by column In the example above I am summing two column, and I would like to use those 2 results in calculating ...
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1answer
221 views

Reducing execution time for this gnarly SQL

I'm creating an order system of some kind. There is a function that I use to get orders (in PHP) and retrieve the required information about the order. However, it seems that I am pulling a lot of ...
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1answer
801 views

MySQL 5.1 -> 5.6 problem, select distinct order by limit query stops using index

I'm testing a MySQL 5.1 -> 5.6 upgrade, and I've run into an issue. I have a query that hits a ~30 million row table, selecting distinct IDs with an order by/limit restriction. Sample query is ...
3
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1answer
703 views

Copy database and clear down data (including linked tables) older than N days

I have a sizable production database (140GB) on MS SQL Server 2012, which I'm trying to automatically download to our development environments on a periodical basis (every week or on demand). I'm not ...
2
votes
1answer
116 views

PL/pgSQL function or rCTE to detect depth of relations between two tables

I need to perform a PostgreSQL Function for checking the depth of relations. There is a circular binding from table a to b, back to another element in a and, in some cases back again to b. These ...
3
votes
1answer
554 views

Simple SQL Query

I have a db that in one column have 5 possible values: "Fechado", "Aberto", "Em Despiste", "Cancelado", "Resolvido". And im trying to do a query that counts the values to a json file var data = ...
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171 views

Combine two mySQL sum queries into one which use different where clauses

I have two sum quires referencing different tables in mySQL. How can I combine the two in order to calculate the difference between the two values for each user in the database? Query 1: SELECT ...
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1answer
72 views

Updating Document in MongoDB without Alphabetically order

I am making one project on MongoDB and inserted some documents and now i am updating the documents by this code.. bson_init( query ); bson_append_string(query, "First", "A"); ...
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1answer
173 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: ...
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0answers
3k views

Nesting multiple INNER JOIN within LEFT OUTER JOIN in sql on deifferent side of keyword

I am having some problems with one of the question's answered in the book "SQL FOR MERE MORTALS". Here is the problem statement Problem Statement Here is the Database Structure The Database ...
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1answer
83 views

Database design Problem for the web-app

Hello I am in a problem of designing a web-app database schema. Suppose I have 10 shops and every shop gives deals on every different day Sunday, Monday and so on and for limited time period like ...
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1answer
65 views

procedure to select the first name of the passed id

I have a table person_name DESC PERSON_NAME Name Null Type ------------- -------- ------------ ID NOT NULL NUMBER(9) FIRSTNAME VARCHAR2(20) ...
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1answer
63 views

Is this statement syntactically correct? [closed]

$q = "SELECT var1, var2, var3 FROM tablename WHERE var_a = '$var_a' AND var_b = '$var_b' AND ( ( var1 = '$var1' AND var2 = '$var2' ) OR ( var1 = '$var2' AND var2 = '$var1' ) )"; This ...
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1answer
300 views

optimize the query with big and low cardinality

I have big enough dataset and few joins to get them all with help next query: SELECT DISTINCT c.c_id FROM c_active z1 INNER JOIN cs c ON (z1.cv_id=c.cv_id) INNER JOIN indi i ON (c.m_id=i.m_id) INNER ...
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1answer
1k views

Restoring a database, changing recovery model

I regularly make a backup of my production database, then restore the same onto a test database, so developers can always have recent data for testing. The production database uses full recovery ...
1
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1answer
123 views

Update different columns on different clauses

I have a database table in Postgres 9.3 with the following layout: id SERIAL, col1 INT, col2 INT Whenever a new row is inserted, I will have to update ALL rows col1 and/or col2 in different cases ...
3
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4answers
474 views

Best practice for a Table with private columns

I have a table with user data, where most of the columns can be public or private (so it will be shown or not on the app) and every user can decide which fields to hide. So far I had a couple of ...
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2answers
221 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 ...
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1answer
39 views

SQL where clause effect on table? [closed]

I have sql query as select sourceIP, sum(sourceBytes) from flows group by sourceIP order by sum(sourceBytes) desc This brings result (dummy) as:- sourceIp SourceBytes 192.168.1.2 100 ...
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1answer
1k views

SQL Parameter Sniffing Possible Workaround

Our system has roughly 500 "Customers" that have extreme differences in record counts. Here is a (greatly simplfied) sample query that could return 0 - 100000 rows depending on the parameter passed. ...
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2answers
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Optimizing large MySQL SELECT WHERE IN clauses

How can the following SELECT WHERE IN case be optimized? I have a table with over 100 million rows with only 3 columns. The primary key (col1) is a 127 varchar. I am performing a SELECT col1 WHERE ...
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3answers
110 views

Select rows where 2 cells not the same

I have the following table: +----+-------+---------+---------------+ | id | owner | variant | EAN | +----+-------+---------+---------------+ | 1 | 101 | black | 1111111111111 | ...
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0answers
20 views

How does database connection actually works? [duplicate]

I am wondering, on a practical level : what is a database connection? What does it represent for PHP/Java/Ruby/etc to have an opened connection for instance? What about the MySQL deamon? Does it ...
0
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1answer
48 views

How to sum the buy order and sell order in one row per each ticker

I have a table containing some trading information of several tickers and I would like to divide the data into sum(Amount) for buy and sell separately, grouping by each ticker. I have one table ...