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

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Join Calender Table

I have a Datatable and a Calendartable. I do a join on this tables to get sequential dates if there is no data for this day. My problem now is that there a several id's and i need a count for each ...
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245 views

Mysql Join with filters

I have two tables: MAINCOLOR and SUBCOLOR with the data as: MAINCOLOR : MAINID COLOR 1 RED 2 BLUE 3 GREEN SUBCOLOR: SUBID MAINID SUBCOLOR STATUS 1 1 PINK 0 2 1 ...
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500 views

Complex query with multiple normalized fields

We have a fairly simple table structure, but with a LOT of fields per table (talking 40+). This data is initially produced in plain-text, user-readable tables, but then it is translated into ...
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2answers
766 views

How to get non repeat results

I've two tables default_tb_persona and default_tb_envio, this are the DDL for those tables: CREATE TABLE `default_tb_envio` ( `codigo` varchar(7) NOT NULL, `fecha` date NOT NULL, `id_modalidad` ...
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How and what is the most efficient way to join two tables, retaining a particular field from both?

I have two tables, with the following columns: Table 1 ID Component Data1 Data2 Table 2 ID Component Data3 Data4 If I have rows in these tables, with items Component1, Component2, Component3, ...
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How does mysql deal with queries that touches myisam and innodb tables?

In our mysql database, we use both myisam and innodb tables, though there are more myisam tables. QUESTIONS If a query involves both myisam and innodb tables, will the query use table lock or row ...
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MySQL 5.5.8 InnoDB Foreign Key, JOIN performance

We are using aws/rds, MySQL 5.5.8. all InnoDB. For performance purposes, we have merged some data-elements into varchar fields; mini-sized int and date type fields; added covering indexes; ...
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769 views

Identify NON-ANSI joins in SQL Server 2008 R2 on a Database that's in 2000 (80) compatibility mode

We have a very old database running on SQL Server 2008 R2. The database is running in 2000 (80) compatibility mode and has oodles of NON-ANSI joins in stored procedures, views and functions. We need ...
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How to use merge hints to isolate complex queries in SQL Server

I can understand that if I join individual queries that are "individually fast" the combination may become slow because the default execution plan may be non-optimal. However when I know the number ...
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1answer
237 views

Is there a standard way to replace codes with values from a lookup table for reporting or analytics?

Suppose I have a "main" table that was probably heavily normalized and consists largely of columns that merely contain codes that are lookups into other tables (they are probably foreign keys but feel ...
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Retrieving data from inner join using LIMIT and OFFSET

These are my two tables: table1 qid[PK] |gid[PK] |abcd | xyz | date ---------------+---------+---------+------+------------ 00001 | qwe | 54 | a | 1994-11-29 00002 ...
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780 views

Group By on column from joined table

its about the following query. EXPLAIN SELECT phrase, infinitiv FROM `dict_verbs_all` `t` INNER JOIN `dict_verbs_all_language` `verbsGerman_c` ON (`t`.`id`=`verbsGerman_c`.`verb_id`) INNER JOIN ...
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367 views

Tuning query to remove joins for reporting

This is the query I was sent. There is currently no data in the system as I was converting this query from teradata to SQL server. SELECT user_id FROM user_table LEFT OUTER JOIN ( SELECT user_id , ...
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254 views

Counting results for cross join

How I can get count results with cross join? Example cross join: SELECT t1.firstname, t2.lastname FROM table1 t1 CROSS JOIN table1 t2
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3answers
1k views

How do I join two tables on two different instances of DB2?

There are two instances of DB2 running on the same machine. One has a table aliased to the a table in the other one. Is there a way to do this in DB2 or does it have to be done via an external tool? ...
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1answer
495 views

NEWID() In Joined Virtual Table Causes Unintended Cross Apply Behavior

My actual work query was an inner join, but this simple example with cross join seems to nearly always reproduce the problem. SELECT * FROM ( SELECT 1 UNION ALL SELECT 2 ) AA ( A ) CROSS JOIN ...
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679 views

Slow query with straight_join for small result

I have a performance-problem with a query in my application and I don’t understand the behavior of mysql. The query consists of different joins, especially the join to the mentioncache-table. If the ...
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Join tables on a partial string match

input: I have a table containing (any number of) user-supplied strings: ╔═══════╗ ║ Value ║ ╠═══════╣ ║ To ║ ║ An ║ ╚═══════╝ And a table of user details: ╔════════╦══════════╗ ║ UserID ║ ...
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Joining 4 tables and 2 counts

I have four tables. UserMaster ---------- UserKey - PK UserName UserID - UNIQUE UserLogTransaction ------------------ UserID - FK:UserMaster.UserID LoginTime LogoutTime CallCenter ---------- ...
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1answer
548 views

SQL Server: join two tables with “valid-to” dates

I have two tables like so: T1_Key, T1_Data, T1_ValidUntil 1 A 2000-01-01 1 B 2000-06-30 2 C 2005-05-31 3 D 2004-12-31 3 E ...
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1answer
93 views

JOIN 2 tables, and query data from them 3 times

Basically I have 2 tables: post_meta and posts. post_meta has a post_id, key and value: post_id key value 6343 make Chevy 6343 model Volt 6794 make Chevy 6794 model ...
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1answer
451 views

Complex SQL Query

I'm trying to formulate a single query to return a nice list of a host's interfaces and the interfaces attributes from the Cacti MySQL DB. Here are the tables I am referencing: host_snmp_cache: ...
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1answer
637 views

Update ranking on table

I have two tables: mysql> desc rank ; +----------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | ...
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1answer
586 views

inner join on PK with extra criteria slow despite indices?

Given the two tables below I am struggling to understand: why is the third query slow even though first two queries are fast what exactly is EXPLAIN saying can I do anything to significantly speed ...
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2k views

Optimizing query using view on EAV structure

An application is writing into a database that follows an EAV structure, similar to this: CREATE TABLE item ( id INTEGER PRIMARY KEY, description TEXT ); CREATE TABLE item_attr ( item ...
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SQL ANSI JOIN precedence

I have a query that looks like this: SELECT * FROM TBLA A LEFT JOIN TBLB B ON A.Col1 = B.Col2 RIGHT JOIN TBLC C ON B.Col3 = C.Col4 JOIN TBLD D ON C.Col5 = D.Col6 In which order ...
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Many-to-Too-Many Relationship

I'm working on a book database. And among others, I have the following two tables (a bit simplified for the question): tblBook: ID, Title tblPerson: ID, Name Note that the tblPerson table contains ...
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739 views

Right Full Outer Join Query

I came across 1 query which is Select * from R Natural Outer Join S Where R=(A,B) has tuples {(1,2),(1,2),(3,4)} and S=(B,C) has tuples {(2,5),(2,5),(4,6),(7,10)}. To implement this I created 2 ...
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Multi-Table Join to Single Destination

I am having a serious performance issue with join together four tables and placing the results (in a certain permutation) into one destination table. I am using MSSQL 2008 and good ole T-SQL. To ...
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2answers
1k views

Select rows with repeat data within certain timeframe

As a follow-up question to my previous question on difficult row categorisation, I have another problem which I'm sure will be easily solvable. After this I plan on reading a good book or two on ...
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2answers
557 views

Count consecutive null rows from a joined table

I have the following tables: members: ---------------------------------------------- | member_id | member_name | member_join_date | ---------------------------------------------- events: ...
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92 views

Efficiency for contact-contact relationships schema

I'm migrating data from a schema where people and organisations are separate tables to one where people and organisations are all treated as contacts (they share a lot in common). Currently, the ...
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Alternative query to this (avoid DISTINCT)

Note: I work with MSSQL 2008, but I guess it's valid for many others DB engines I have this table "Users": UserID User CountryID 1 user 1 1 2 user 2 2 3 user 3 3 4 user ...
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Unable to add records to query in Access 2007

I've found this excellent resource that covers why a query might be read-only. I have a query that is not read only, yet I'm unable to add new records to it. There are three tables. Let's call them ...
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1answer
520 views

Should I use left join to do my job in this scenario?

What I want to do is to find out the items which appeared more than once in this table: mysql> desc tables; +-----------------+---------------------+------+-----+---------+-------+ | Field ...
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5k views

Joining two tables on multiple criteria

I have two tables products and positions. products: id BIGINT PRIMARY KEY, product VARCHAR(100), criterium1 VARCHAR(100), criterium2 VARCHAR(100) positions: id BIGINT PRIMARY KEY, position ...
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CROSS JOIN with temp table and CASE statement

I'm trying to CROSS JOIN a table with a view. Here is my code: SELECT * FROM ( SELECT * , CASE TypeId WHEN 1 THEN InGs828S WHEN ...
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SQL Server does not optimize parallel merge join on two equivalently partitioned tables

Apologies in advance for the very detailed question. I have included queries to generate a full data set for reproducing the problem, and I am running SQL Server 2012 on a 32-core machine. However, ...
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191 views

Querying multiple tables

I am working on a query from our ticketing system, and I am having problems figuring out the best way to join these tables together. I have the following tables/fields: SR_service: stores ticket ...
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117 views

Long JOINS Returns No result all tables have one to many relationship with a particular table [closed]

I have a Table Enterpries with Primary Key 'RCNO'. All other tables have a one to many relationship with Enterprise via it's RCNO column. I make a Join of all the tables and i get nothing. Below is ...
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2answers
981 views

In DB2, how can I disable NLJOIN?

I want to indicate to the optimizer, via SET or optimization profiles, that NLJOIN shouldn't be used at all when optimizing a query. I've been looking for this for a while without any success. I ...
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5answers
2k views

Does 'Cities' deserve a separate table?

I have the following Customers table: customer_id - int company_name - nvarchar street - nvarchar city - nvarchar comments - nvarchar The app will only be used in part of one small country ...
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1answer
5k views

how to fetch different data on compare rows of two tables

I have two tables in my database, one is user_app table in which user info are stored, table are as: +--------------+--------------+------+-----+-------------------+-----------------------------+ | ...
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INNER JOIN making COUNT(*) slow

I have a very simple query: SELECT COUNT(*) FROM messages INNER JOIN users ON messages.user_id = users.user_id With the join it takes 1146 ms and without it takes 220 ms (220 ms still seems slow to ...
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666 views

Mysql Join to get multiple row value from

I am new to my Mysql and need help regarding join I have a table called employee and this table contain some foreign key value like phone, address, sex. Table phone and address have 4 rows in it, I ...
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1answer
934 views

Slow performance of MySQL Join Query

I have inherited a site (running Coldfusion8 and MySQL 5.0.88) with a product search using multiple criteria. I'm struggling with optimizing the search, especially a pricelist check, which makes the ...
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Is adding rows better then adding columns in case their value is not consistent?

In my project I have a table of customers, each customer has his own special price for each product, It's a small business and there are currently about 5 products. The manager says there might be ...
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How can I select the latest record having one state where no later records exist with any other state?

I want to select the last record (by datetime) having a given state where no later records exist with any other state for each given "widget". widget state timestamp ------ ----- ...
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MySQL: Very slow query, not using index, no joins involved

I am running what I think is a very simple query: SELECT SQL_NO_CACHE m.mbr_nbr FROM tran.member m WHERE m.cardnbr = 000099999930 The table member is a poorly written one, with 133 columns and ...
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1answer
670 views

Help with a complicated MySQL Query inserting data using select from 2 tables

I am stuck with a case and unable to get the desired result from my query.. I have to insert into a table some records based on multiple records from 2 different tables.. Tables: Target: ...