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

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How to join fixed row table against mapping table and reveal unmapped records

I have two tables and I am having trouble figuring out how to join them to meet my projection needs. Here is a scenario that illustrates the problem 1. The first table has a fixed set of values/rows; ...
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86 views

SELECT query with DISTINCT on a table-structure for graphs is very slow

I have 2 tables where nodes contains about 60m rows and edges about 500m rows (both growing fast). These two tables represent a directed graph. CREATE TABLE edges ( node_from bigint NOT NULL, ...
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185 views

How to improve the performance of SELECT queries with multiple JOINs on a 50GB database hosted on AWS m3.medium MySQL RDS?

Example query: SELECT p.ListAgentEmail, p.ListAgentFirstName, p.ListAgentLastName, p.ListingKey FROM Property_RES AS p INNER JOIN Property_RES_COUNTIES_OR_REGIONS ON ...
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108 views

SQL SELECT - adding field to SELECT with JOIN is changing the results

I have a SQL sentence with JOIN, running on mysql 5.5.16: SELECT DISTINCT (ot.orders_id), ot.value FROM orders_status_history osh INNER JOIN orders_total ot ON ( osh.orders_id = ot.orders_id ) WHERE ...
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237 views

Does MySQL load the entire row into memory, or just the columns used in WHERE, ORDER BY and GROUP BY?

I have a table that isn't very large row wise (in the 100ks range), but that contains a lot of raw data that is very large in size. Despite having a relatively little number of rows, it's around ...
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Get all (non repeated) distribuidores with their paises given a producto_solicitud

I have this schema: And as title says I need to get all records from fabricante_distribuidor by given producto_solicitud.id value. I'm doing in this way: SELECT ...
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67 views

Sort by number of related rows in referencing table

Let there be two tables: Users id [pk] | name --------+--------- 1 | Alice 2 | Bob 3 | Charlie 4 | Dan Emails id | user_id | email ----+---------+------- 1 | 1 ...
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41 views

How to join a table with a table valued function?

I have a user defined function: create function ut_FooFunc(@fooID bigint, @anotherParam tinyint) returns @tbl Table (Field1 int, Field2 varchar(100)) as begin -- blah blah end Now I want to join ...
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113 views

Minimizing Page Fetches

I have a complicated database structure and am trying to use it to retrieve Records based on multiple selection criteria from several tables. As a general rule, is it better to attempt to use ...
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MariaDb join 2 table with diffrence storage engine [closed]

As you know, MariaDb has a lot of special storage engine like: Cassandra, TokuDb, ... Can I join 2 table with different storage engine in one SQL query? eg: 1 cassandra join 1 tokudb,...
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19 views

SQL query to aggregate data from three tables

I have the following three tables: The "users" table: user_id first_name last_name username password The "users_addresses" table: address_id user_id street country_id email The "countries" ...
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110 views

SQL join with multiple columns as FK to same list table

I have a table that has 5 references to a list table for normalization of the first table. So in the table 1 a row looks line other columns..., reference_1, reference_2, reference_3, reference_4, ...
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197 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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20 views

MySQL join for two queries

I have the following two queries... mysql> select id, title from events; +----+-----------------------------------------------------------------------------------------------+ | id | title ...
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1answer
257 views

Sql server table insert performance optimization

Setting In a datawarehouse, I am joining a fact table to 20 dimensions. The fact table has 32 million rows and 30 columns. This is a temporary staging table so I don't have to deal with other users ...
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190 views

Data Analysis with MongoDB or MySQL

I have a need for processing some data in order to come up with some statistic. This is the scenario: Each user can answer several questions from the question list. They pick their answers from a ...
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2answers
68 views

PostgreSQL joining using JSONB

I have this SQL: CREATE TABLE test(id SERIAL PRIMARY KEY, data JSONB); INSERT INTO test(data) VALUES('{"parent":null,"children":[2,3]}'); INSERT INTO test(data) ...
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140 views

Joining on a field with different values

I am trying to join data from two completely different sources. One source contains an employee's schedule information, and the other tracks what they actually worked (like what time they actually ...
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MySQL Multi Count and Filter

Table: Event ============== ID OldUserID NewUserID Date Table: User ============== ID Forename Lastname .... How can i filter by date column like so... this code is pseudo... SELECT ...
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2k views

How to create the multiple sum query with joins

Please consider following database: Table `invoices`: -- invoice_id Table `amounts`: -- amount_id invoice_id type_id amount I am trying to get the sum for each type from table like this: SELECT ...
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24 views

optimize my query mysql

I have the following query: SELECT DISTINCT d.movieName, d.castName, d.movieImdbId, f.year, f.posterLink FROM director_movie as d LEFT JOIN film_info as f ON d.movieImdbId = f.ImdbId WHERE d.castName ...
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25 views

Simple left outer join leaving me with inner join

So I have a table with each record being a change to an object. e.g. in the app you open your project with a project id in this project you edit an object name hit save that generates new record ...
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Is it better to separate a big query into multiple smaller queries?

There are situations which require having really big query joining several tables together with sub select statements in them to produce the desired results. My question is, should we consider ...
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Build a three table join with a recusive table in the middle?

I have three relevant tables: Parts, PartGroup, and MarkupGroup. Parts is simple. PartID artificial primary key Part part number PartGroupID Foreign key sample data: 1 ...
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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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Massive joins Vs Updating temp table

I'm working on a query that essentially aggregates a slew of tables together. The first method I tried was to inner join all of the tables into one nice big query that pretty much looked like this: ...
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Summarizing Pay Checks Based on Employee's Job Code

What I'm trying to do is summarize an employee's earnings for each job code they worked in for the year. Employees are assigned a job code based on an effective date. I'm trying to line up the job ...
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Joining two Mysql VIEWs takes a very long time

I have a textbox (for which I used jQuery auto-completion) in my PHP form where user can insert an actor/actress name and then by clicking "Search" button, a new window is opened showing list of ...
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50 views

How can I simplify this UNION?

Here's the case - I have the following query: SELECT DISTINCT post_id FROM ( ( SELECT DISTINCT rp.post_id, pm.meta_value AS premiere_date FROM wp_related_people AS rp JOIN ...
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54 views

Companies and addresses MySQL [on hold]

I've got a database with 2 tables. companies addresses These are my tables. Adresses adress_id adress_adress adress_adressnumber adress_zipcode adress_city adress_postbus adress_country ...
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87 views

How can I optimize this Cross Table COUNT() mysql query?

I am trying to cut down the retrieval speed of this MySQL query. All instances of COUNT() point to the PRIMARY key of each field. Currently this query makes my MySQL hang. It seems ridiculous as I'm ...
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44 views

Join select queries on an id in SQL Server

I have three tables that SELECT from and I'd need to join the results. It feels like this should be a rather easy task but I struggle with the syntax. Working on Microsoft SQL Server Enterprise ...
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37 views

Select two aggregate functions on the same column using different criteria - performance

Dear stack exchange users, first question here. The database in question is a service database where a user hires a service. Now I would like to show the person that was hired an overview of how many ...
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40 views

How to manipulate join order of PostgreSQL optimizer?

I am working on table join order optimization. While query processing, I want to get table join order generated by optimizer, and update it by using my own algorithm in PostgreSQL? How can I update ...
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60 views

mysql join not working as expected

i want to select schedule of specific teacher for a given day .... statement should assume that a teacher may teach in elementary and high school here is my statement `select class.name as ...
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63 views

Query optimization for multiple joins postgres

ER Diagram Brief description The database to be used is postgres. The database might contain upto 2 million AccountHolder records. Since the AccountHolder table is accessed and updated frequently ...
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32 views

Updating MySQL innodb table based on multiple joins

I have a table with the following (slightly simplified) structure CREATE TABLE `oak_relation` ( `o_id` int(10) unsigned NOT NULL, `k_id` bigint(20) unsigned NOT NULL, `initial` float unsigned NOT ...
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MySQL improve query syntax

I have this simple MySQL query: SELECT * FROM table1 INNER JOIN table2 ON table2.col = table1.id WHERE table1.id = '123' id is the primary key in table1. table2 has composite primary key of two ...
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25 views

Join does not not use index in PostgreSQL?

I have a statement that selects from two tables news and status. It seems that the index on the column status of the table news is not used. This table has about 70.000 rows and the query costs too ...
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56 views

Equality in JOIN or WHERE clause? Efficiency and style

Of the two queries below, which is the most efficient for postgresql? And which has better style in terms of readability, etc. The difference is the placement of the statement doctor.type != ...
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“DISTINCT” JOIN in mySQL [duplicate]

+----+-------------+-----------+---------+ | id | login_ip | hostname | user_id | +----+-------------+-----------+---------+ | 1 | 192.168.0.4 | 'host 1' | 1 | | 2 | 192.168.0.4 | 'host ...
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36 views

Best way of finding rows referencing a given id on PostgreSQL

I'm trying to find if there would be anything violating the foreign key constraint when deleting a row, to check if I can delete it or not (can't use ON DELETE CASCADE) For that, I have a piece of ...
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Large Data Long Query A Lot of Joins horibble performance

I have 3 Tables Person, Family, City Person Table (6 Million Rows) id (primary key auto_increment unsigned) family_id (index) city_id (index) full_name first_name (index) last_name (index) ...
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29 views

Stacked Left Joins or Left Join inside a Subquery?

OK, this is a fun one. Designing a database for a gaming system. I have 3 tables that are relevant for the query I'm trying to work on right now. character_skill_log with the relevant fields of id, ...
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815 views

Self Join? Or am I wrong?

We have a table that we use to store customers and items. We need to be able to find customers that have bought one item and have not bought another item: customer item Sally 1 Sally ...
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43 views

MySQL update one table from another joined many-to-many

I have two tables, events and plays joined many-to-many by a third table plays_in_events. Where the events.Name field is blank, I want to set it equal to the name of the play that was performed in ...
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Receiving duplicate results in one condition of JOINED query

I always end up here when Googling for solutions, so I thought I'd cut out the middleman since I'm unable to fix this via searching/forums. It's my first time posting, so please forgive any faux pas ...
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Group_by and having vs Joins when table is self joined 5-6 times

Now the situation due to which this question came to me. Schema is Table User_Read_Book user_id | book_id Now I want to get users who have read certain books. Say give me users who ...
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109 views

Merging tables, but ignoring duplicate columns

I have two tables I want to merge: city1(id, city, state, zip, lat, lon, county) city2(id, city, state) The tables contain overlapping city and state, but not primary keys. I can't figure out how ...
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31 views

Help on MySQL joins

I'm building a system to monitor currency prices. Part of my database structure looks like this: My system is trying to pull the api ticker for each exchange with this query: SELECT distinct ...