An SQL join clause combines records from two or more tables or views.

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SQL Server query problem when selecting data from child table based on column in parent table

I am using MS SQL Server 2008 using Management Studio. I am running a query(below) to extract dates and value based on the 'ticker' column from the parent table, the attribute column (child) , and ...
2
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145 views

join to other table multiplied by loop foreign key in mysql

i have 2 table one node and relation and Second store buy each node. my code work fine but when sum multiple buy for each node result multiplied by number of purchases . table nodes +-------------+--...
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146 views

Include logical key on each table vs. join

I'm designing a database that is used to track an inventory item through its lifecycle. I'm currently relating my tables using the previous lifecycle event's ID (for example, a shipment contains the ...
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1answer
109 views

Compare two tables with same structure, but differing membership numbers

I have two tables with the same structure and most of the data is the same. I also have a third table that contains ids and names. The ids are connected to the membership numbers discussed below. The ...
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2answers
690 views

Mysql improve Self join performance large table?

I have a task to help identify conflicting IP ranges , I want to highlight when one companies IP range falls within another's ... below is the sample table, I have converted the IP ranges from .dot ...
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26 views

counting and sorting join mysql

i have table like bellow it store of amount of buys of each user +--------+----------+ | userid | amount | +--------+----------+ | 1 | 1000000 | | 2 | 80000000 | | 3 | 7000000 | | ...
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304 views

MYSQL joining 3 tables with left join

I have these tables: pupils: (id_pupil, name, surname, email, user, pass, level, class) incidents: (id_incidents, date, time, type_incident, comments, id_pupil, id_user, subject, id_trimester) ...
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50 views

View created using Join Queries taking too much to load

I have written a query to create a view which i can use as a flat table in my application, which is having more than 30 inner join conditions across 25 tables. Now the problem is every time i am ...
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1answer
67 views

How do I correctly group output from multiple tables?

I have more than 2 tables where entries are associated with dates. Each table can have multiple entries per date. I want to produce output that lists a date, then lists the entries of each table for ...
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210 views

Adding 4th table to join jumps processing time from seconds to over 20 minutes

I am trying to join a total of 4 tables together. When I only join 3 of the tables together I get a result set of about 220,000 records in about 2 seconds, but as soon as I throw the 4th table in, the ...
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Primary key index not used when using inner join with jsonb_array_elements subquery on Postgresql 9.5

I have two tables: hub and huboperator hub table is defined as CREATE TABLE public.hub ( parent_hub_id integer, ancestors jsonb, descendants jsonb, name character varying(1024), id integer ...
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38 views

Speed up SUM() on a result with JOINS in MySQL

I have a query with a combination of 6 left joins and inner joins. The query gives a result of 25000 records in 112ms. When I do a SUM() the query takes 4s. A SUM() another table with 35000 records ...
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Join between a table and a recursive table

I've that two table, I know they are not well thinked but my client did this tables and I cannot change them. TABLE A id | codigoFatherTABLEB | codigoSonTABLEB TABLE B id | name | codigo | idPadre ...
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97 views

How to JOIN more than two tables?

Following is the schema of my Tables: Marks_Table (SubjectCode,TypeID,MarksObtd) Subjects_Table (SubjectCode, Subject) Types_Table (TypeID, Type) I want to Select the Marks_Table table with ...
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38 views

Single value from a list of comma separated values when used in inner join in SQL Server

Can anyone please help me with a query to return a single value from a list of comma separated values when used in inner join. I can paste the example query here. select * from Test.dbo.Test1 ...
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40 views

Selected Child Categories based on parent categories from another table

I have two tables rules With three step hierarchy: |id | name | parent | |---|-------|--------| | 1 | A | 0 | | 2 | B | 0 | | 3 | A(1) | 1 | | 4 | A(2) ...
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42 views

MySql - Get all children in JOIN if one child matches a condition

I have a one-to-many relationship between two tables Parent and Child. I want to get all children if one child matches a condition. Something like below: SELECT * FROM Parent p INNER JOIN Child c ON ...
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58 views

Simplify Month Over Month % Change, 4 Months Moving Average %

invoice created_at | amount | status | ------------+--------+--------- 2016-06-01 | 50 | 2 | 2016-05-30 | 150 | 2 | 2016-04-29 | 32 | 2 | 2016-03-28 | ...
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74 views

Delete query does not end

I have a following table with 1 million records : CREATE TABLE `activity` ( `id` int(9) unsigned NOT NULL, `user_id` int(10) unsigned NOT NULL, `subscription_id` int(10) unsigned NOT NULL, `...
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28 views

Postgres LEFT JOIN with recurring dates and users

I'm trying to get a query to show me if users have a record on a particular day, and if they don't it would return a NULL. What I have so far is a I create a sequence of days, then LEFT JOIN it, if I ...
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51 views

Do Large Hash Joins Contribute to Stolen Pages?

On a SQL Server 2014 SP1 Enterprise Instance, I'm performing an outer join between two partitioned tables on a numeric(16,0) + char(1) composite key. 100 GB is the max server memory setting on a 128 ...
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33 views

Updating rows in multiple different tables using JOIN

Following is my MySQL SELECT query and it works. SELECT candidates.CandidateName, candidates.CandidateVotes, candidates.Party, candidates.win, candidates.NameOrder, ...
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Decomposition and lossless joins

If someone walk me though the following questions I'd be very grateful. Consider a relation R(A, B, C, D, E) with the following functional dependencies: A, B → C D, E → C B → D i) ...
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How does the use of derived tables speed up sorting?

In the article 45 Ways To Speed Up Firebird Database, it states that Use derived tables to optimize SELECT with ORDER BY/GROUP BY Another way to optimize SQL query with sorting is to ...
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1answer
93 views

Estimate result size of Natural Join

I have the following tables R1(A, B, C) with 1.000 rows R2(C, D, E) with 1.500 rows R3(E, F) with 750 rows where a bold letter denotes a primary key. I need to estimate the number of rows of the ...
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22 views

Unique pair checking query improving in pivot table

First of all, I have a solution, but I do not know that query can be transformed to uses join or to more effective query. I just want to improve my skill. I have seen an example online. So I have a ...
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89 views

What is difference between JOIN and simple query

I have two tables in database one is Orders and another one is customers Orders Table Contains : OrderID , CustomerID and OrderDate Customers Table Contains: CustomerID , CustomerName , ContactName ...
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80 views

Update table using values from another table in SQL Server

I have 2 table in my database. Table #1 ------------------------------------------------------------------------- | name | family | phone | email | gender | phone2 | address | birthdate | -----------...
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100 views

SQL query to count number of payments made in a time period with data from two different table

Could someone please tell me how to write sql query for the following question? I am not able to get how to write the condition where it selects those user_id which is present on the said date and ...
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1answer
210 views

Select multiple columns from subquery - Connect by

I have a table which manages folder structure. Hence it has a parent-child relationship. We trigger a query to sum all documents in the complete heirarchy: SELECT folder_name name, ...
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1answer
34 views

How to get average of views before clicking on advertisement?

I've got two tables containing information about viewing and clicking on advertisement by each user: Clicks: userID Action Time 123 c 2016-01-08 01:57:00 123 c 2016-01-11 ...
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49 views

Query to find missing status events

I'm hitting a road block as the best way to query a related table. I have two tables: main and status_history. Right now, I can identify records from main with no status_history at all, but I need to ...
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MS sql query value one table but not another join table where*

I have [tbl_AllStudentsEmail] where I get my students distribution list. I also have [tbl_CourseID] where some students are registered (not all). Students record are registered here along with the ...
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33 views

Access Web App query 3 Tables with aggregatios - Need a workaround

I'm designing an Access 2016 Web App for inventoring our computers. The problem I have is with a query where I want to get the CPUCore-amount and RAM-Amount for each PC. The computer-value in RAM ...
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40 views

Does the EXIST clause only return distinct rows by its nature?

I have two queries that appear to be logically equivalent, yet they return different result sets. I am using the AdventureWorks2012 database. The first query uses an EXISTS clause with a sub query. ...
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3answers
91 views

Join between different frequency tables

Assume that I have two tables, DailyTable and QuarterlyTable, where each have 3 columns: ID, Date, and Value. As the names indicate, the frequency of data stored in DailyTable is daily, while the ...
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117 views

How can I pivot a view into a join so I get multiple query rows as columns in a single row? [duplicate]

I have a view into which I am pulling properties of vehicles, such as tire size, engine capacity, color, number of doors, etc. This data is stored in multiple tables but I have simplified the data ...
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2answers
60 views

How could I get the value as Y or N in one table if value is exists on another that meets certain condition?

I have to generate simple report from three tables named customer, product, and order. My report should have a column that shows whether the customer ordered that product or not. How could I get the Y ...
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1answer
49 views

PostgreSQL join subquery can't restrict query

I'm working on a check-splitting project that splits out amount owed for an activity. Users can be a part of multiple 'groups', which each have their own running balances. I'm trying to run a query ...
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47 views

How to give a prefix to all columns of a JOINed table in MySQL?

I have a data schema like this: car id type -> ENUM('Tesla', 'AstonMartin', 'Bmw') common_attribute car_tesla car_id specific_attribute_a specific_attribute_b ...
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1answer
53 views

How to JOIN a table with a name that equals to a determined value in MySQL?

The model of the (PHP & MySQL based) Zend Framework 2 application I’m currently working on contains a inheritance similar to the one described here. To map this to the database I’m using the ...
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69 views

comparing left join and outer apply doing the same thing

I have an update trigger on a table that that insert rows in another database/table the query look like insert into otherdb.table select manyfield from inserted left join (select id, ...
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1answer
32 views

ORA-00932 on subquery join from subquery join

The only guess I have is that perhaps the size of the subquery is considered a CLOB? I have no null values for the fields selected AFAIK. SELECT DISTINCT kbq_ent.qid AS kbq_ent_qid, kbq_ent....
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3answers
113 views

Poor performance of JOIN, WHERE, ORDER BY combination (MySQL)

Goal: select 10 most recent rows from posts which are related to a specific user. There are two tables: posts (~5,000,000 rows) and relations (~8,000 rows). posts columns: --------------------------...
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1answer
26 views

Query: How to join on different tables depending on the filled column?

I'm pretty new to the field of SQL, but already solved a lot of problems, so until now i am familiar with the different possibilites of JOIN(s) (explicit and implicit syntax), group by, distinct and ...
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1answer
31 views

Using a join operation with conditionals

I have two tables that I'm working with in my database. I am using SQL Server 2014. One is 'versions', that contains version_id, version_number, start_date, end_date and server_id. The other is '...
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54 views

MySQL Query fix and speed up

I'm newish to MySQL and a lot of my query is pieced together from this site and trial and error, so any help is appreciated. If I left out anything, or more detail is needed, I will be happy to give ...
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33 views

Multiple references to another table, but I don't know how many

I have two tables in a database, folowwing this model: scientists : id (int) | name (varchar) | surname (varchar) | publications (int) publications : id (int) | fulltext (varchar) I would like to ...
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How to avoid row locks on both tables joined in an update?

I have little knowledge about MySQL internals, but I'm experiencing that in a query like: UPDATE t1 JOIN t2 ON t1.id = t2.id SET t1.a = x, t1.b = y, [, ...] WHERE [ ... ] rows from both t1 and ...
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2answers
391 views

Outer self join filters vs subqueries

I have a table storing information about tickets. There is one record when ticket is sold and another when ticket is used. There is a column called TransType which is set to either 'sold' or 'used' ...