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

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inner join select - group by?

I have 2 tables (Oracle database): ANEXA2A_TABEL1: id fk_id_anexa pet1 pet2 alt1 alt2 1 123 10 1 20 2 2 321 11 2 10 3 ...
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1answer
27 views

making a where clause optional in a sql statement

Here is my current query: `SELECT `performers`.`hash`, `performers`.`alias`, `performers`.`date_updated`, `performers`.`status`, IF(`performers`.`status` = 'active', 'deleted','active') AS `...
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1answer
610 views

Oracle 11g hash join vs nested loops question

I'm using Oracle 11g and working on a legacy system. I have two tables, A and B. A has ~40M rows and B ~4M rows. A has a foreign key on B (B is the parent of A). A query does essentially this: ...
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0answers
117 views

How to display additional column in select with true/false value [SOLVED]

Solved. Look in comment. I am using PostgreSQL 9.1. I have 3 tables: simcards: id serial NOT NULL, iccid character varying(30) NOT NULL, customer_id integer customer: id serial NOT NULL, name ...
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1answer
40 views

Meaning of JOINs in sql

I was trying to interpret the relationship between JOINs like LEFT-OUTER JOIN, RIGHT-OUTER JOIN, etc with relationships like Many-To-Many, One-To-Many etc in Hibernate or database language.
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338 views

Performance hits with MySQL Left Joins and Order By

There are a lot of questions out there regarding this issue, but most answers seem to be very case-specific. I've tried to make this general so it'll help others too. The Issue We have a smallish ...
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1answer
24 views

Table for actual values

I have a database where logging happens and is processed in a data-warehouse styled environment. This means there are staging cycles where the data comes in and then is processed. For a reporting ...
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1answer
122 views

How to join SQL tables where value is Between min and max value

I am currently looking to join two tables together based on an IP and IP range. Both the IP and Range are currently stored as BIGINT. For example we have a table MasterData with IPs in integer ...
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1answer
50 views

Converting a GraphDB schema to a relational database schema

I currently am using a graph database and am considering moving off of it to a relational database like Postgresql. My concern is that I have lots of relationships between entities (since this is ...
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2answers
243 views

MySQL - Creating an associative table

I have the following table structures: Cases: (PK) case_id | case_notes | time 1 | blah | timestamp 2 | blah | timestamp 3 | blah | timestamp . | . ...
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2answers
458 views

Inner Join and Right Join same query

I'm using MySQL and InnoDB, I have a table reserver with 2 columns : idReservation and idChambre I have a table reservation and a table chambre Now I want my query to return every "chambre.id" who is ...
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1answer
368 views

Is it possible to simplify a query with multiple joins to the same table?

I have a rather large query which takes longer to run than I would like because of 17 LEFT JOINs on the same table. I've done some searching, but haven't found anything that is really similar to my ...
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1answer
342 views

Optimizing Join between a very small and a very large table

I have two tables: CREATE TABLE `TBL_REPORT` ( `ID_TBL_REPORT` bigint(20) NOT NULL AUTO_INCREMENT, `INDEX_NAME` varchar(100) NOT NULL, `INDEX_VALUE` varchar(100) NOT NULL, `...
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1answer
555 views

Query data from two tables and substitute foreign keys of first table with values of second [closed]

There is data table mysql> select * from data; +----+--------------------------------------+ | id | uid | +----+--------------------------------------+ | 1 | ...
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0answers
31 views

Subquery optimization

I was reading through this article - http://explainextended.com/2009/09/18/not-in-vs-not-exists-vs-left-join-is-null-mysql/ I am working with an existing design. What I want is to be able to select ...
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1answer
106 views

Select range of non-identical date from different table

On MySQL5 with innoDB, I have sensor data in multiple tables, all with an ID and a DATETIME field, like so (two tables shown, but there are more). The IDs and DATETIMEs are not identical between ...
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1answer
703 views

LEFT JOIN DEFAULT NULL VALUE

My query can be simplified as this: SELECT a.id, a.name, b.* FROM a LEFT JOIN b ON a.id=b.id Which b is from group concat select (very dynamic column). Sometimes there are 3 columns in b, sometimes ...
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1answer
154 views

Select max value from many to many tables

i have next tables in may data base: I want to select the book that has the max number of pages for each author. I did this : select auteur.nomauteur, auteur.prenomauteur ,livre.Title, livre....
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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 ...
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1answer
52 views

Uniq join 3 tables with relationship table not uniq

I am using Postgres. I have 3 tables: table_1 id table_1_2 table_1_id, table_2_id table_2 id The problem is the relationship table table_1_2 is not uniq. I.e., table_1_2 will have the ...
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1answer
130 views

placing conditions in a join query join on vs where

Is there and advantage to one of the following options over the other or are they the same ? select * from T1 Join T2 on T2.id=T1.t2_id and T2.field=value; vs. select * from T1 Join T2 ...
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1answer
325 views

Creating Database Tables for Reviews functionality that incorporates Tags/Categories

I'm wanting to create some simple website functionality through a little database idea I have in order to give myself the ability to create/retrieve customer reviews based upon tags/categories. More ...
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1answer
789 views

Select on multiple tables with group by

Using Postgres 9.3, I have problem with a select over few tables. I have simcards stock and I would like to get something like this: | network | supplier | total topups (EUR) | 1st topup qty| | ...
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127 views

MySQL - Group By - How does it determine which row to return from joined table

I am getting desired, but inexplicable behavior on a particular query, and wanted to get more information before pushing up. I have 3 tables: foo bar bar_image And paring back all distractors, ...
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0answers
102 views

Poor performance filtering mysql spatial join

First of all, sorry for the crossposting. I ask this question in stackoverflow and they sent me here I have a mysql table with spatial references (GEOGRAPHIC_FILTER), like cities, countries, natural ...
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1answer
583 views

Better way to select from nested tables in PostgreSQL

I have the following schema with millions of rows in the match table and each match have two sides (away and home). I want to create a view which shows the most significant data regarding the matches ...
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2answers
459 views

Join 2 columns in one table based on equal values in a third column

I am trying to separate data within one column based on identical values in a second column. Our goal I to find out how many times each MD used a facility. Unfortunately, the table has separate ...
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39 views

Adding counts inside a COALESCE

So I have a continuation of this question. New requirements have thrown in a third table. So here's the breakdown of how the tables relate: TabA(TabA_id, desc) TabB(TabB_id, TabA_id) TabC(TabC_id, ...
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1answer
36 views

Need help rectifying IN/NOT IN clause

Hi there everyone! I have built a link/content sharing site. The way it works is that each link can have multiple categories assigned to it. A video of a motorcycle race might have motorcycle, racing,...
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2answers
699 views

Join multiple Tables by date

i got some problems on my approach to join a couple of tables by a date range. This are my tables: RETURNS: RETURN_DATE RETURN_AMOUNT 02.05.14 2 02.05.14 3 02.05.14 1 02.05....
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1answer
26 views

Adding a column to aggregated data where new value only applies to a subset of the aggregation

Having trouble explaining this. I have a table like this: Label | Value A | 3 B | 1 C | 4 And another like this: Label | Value | ID A | 1 | ID1 A | 1 | ID2 C ...
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1answer
249 views

How to put the results of a query into a variable?

I have written a Postgres anonymous block. In which I have written join query on multiple tables like: select a.portal.*, a.p_fb_config.*, a.p_gplus_config from a.portal left outer join a....
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Is it a better idea (performance is key) to store in a normalized table and retrieve by JOIN or in a single nvarchar column and retrieve using LIKE?

NOTE: The application is not really about websites or keywords, I am using that here only to provide reference points for discussion. I have a data set that is really just a string of words. Think of ...
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2answers
172 views

Query to return zero if nothing exist

I have a table With currency, paymenttype and invoiceamount. I have to write a query to get currency, paymenttype and total invoiceamount made. This is pretty simple with group by. But actually I ...
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1answer
75 views

How to split a multivalued column, do a lookup and update another column?

This is a part of my previous question. How can I achieve the following for all the records in my table using a single query? SET @TeamMembers = TeamMembers from tblProjects where ID = '125' ...
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0answers
41 views

How to get list of ids from joining two tables (one to many) whose results is not present in a list?

Say Table 1: tID, tName Table 3: t2ID, tID, tSubjects One tID can be have multiple t2ID. What I want is list of tIDs who's t2IDs should not just have a list of t2IDs (1,5,6). i.e They can 1,2,5,6 ...
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389 views

Limit relation one to many or one to one

In a relationship one to many or one to one you can limit the relationship of the related table? For example, I have a table 'cliente' and another 'acct', each 'cliente' can have thousands (perhaps ...
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1answer
78 views

Mysql query giving incorrect values [closed]

When this SQL query is executed it gives incorrect value, please advise select sum(cash_management.cash_in), sum(cash_management.cash_out), sum(cash_management.pay_in), sum(...
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2answers
46 views

Join that returns always 1 record

I have a table that holds tests. For every test you have a generic one (TYPE field is NULL) but for some tests you can have also more specific tests (TYPE field has a value). I need a join to this ...
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1answer
21 views

Outer join with blank spaces to accomodate both sides

I am trying to join two tables both relating to cities. One table has the columns City and Writer, the other has City and Park. I want to end up with a table that has the columns Writer City Park. If ...
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3answers
4k views

Find duplicate records across one-to-many relationship tables

Let's say I have two tables that have a one-to-many relationship: People and Attributes. I'm trying to find duplicates based on the first_name, last_name, and all attributes must match exactly. ...
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1answer
443 views

INSERT multiple values via join

I have three tables, representing two entities and a connection relationship. Each of the entity relations has an artificial surrogate key used for foreign key constraints in place of natural keys. ...
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2answers
160 views

Creating joined rows from multiple tables on date field

I need to be able to take Table A and find the records that match in Table B and Table C based on its ID and add them together. The trick is that I only want to add the results from Table B and Table ...
0
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1answer
49 views

Mysql JOIN with 25million rows

Recently I got stucked with a table where its grown to +25million and I have got a query that's doing a JOIN on it. The query take 2.5hours to execute even though I got Good 96GB RAM and RAID10 with ...
2
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0answers
31 views

Query optimization - contact should be extracted at most once for a particular customer

I have created a database for a telemarketing company Scenario is, the telemarketing company is selling contacts to the customers. Customers log on to the website and search for the contacts for ...
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2answers
205 views

1 hour query, is there another way to do this?

I saw a couple questions similar to this but none could answer my question, really. I have two tables, and I am trying to find those rows where a match is found. user has about 350,000 entries and ...
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286 views

count rows with same value and get column from other table

I'm trying to count product numbers for a period of time there are three tables. invoice (table) Column Column ------------------------------------------- |invoicenumber ...
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1answer
2k views

How to use a group by in inner join

I have Two tables: Table 1 ID totalamount --- ----------- 100 1000 101 500 Table 2 ID Individualamount --- ---------------- 100 500 100 300 100 100 101 200 101 300 I Need a result ...
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2answers
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Calculating percentage from two tables

I have two tables: First one contains unique mentees under one mentor, so mentors can have more than one mentee in that table. Second one contains interactions of mentors with mentees on different ...
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1answer
186 views

What's the point of SQL joins if you have OLAP?

I want to understand the purpose of using SQL joins from a business analysis perspective. Let's say I want to analyze customer data. Why would I want to pull data from multiple tables using join ...