An SQL join clause combines records from two or more tables or views.
0
votes
1answer
155 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 ...
0
votes
2answers
173 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 , ...
0
votes
2answers
62 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
4
votes
1answer
191 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 ...
2
votes
2answers
85 views
Joining 4 tables and 2 counts
I have four tables.
UserMaster
----------
UserKey - PK
UserName
UserID - UNIQUE
UserLogTransaction
------------------
UserID - FK:UserMaster.UserID
LoginTime
LogoutTime
CallCenter
----------
...
0
votes
2answers
194 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 ...
-3
votes
3answers
420 views
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 ║ ...
2
votes
1answer
77 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 ...
3
votes
1answer
152 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:
...
0
votes
0answers
112 views
Which update is faster using join or sequential?
My this question is in sequence of my previous question I asked.
I could write two solutions using Stored Procedure instead of trigger or nested-query .
Both use a helper function ...
2
votes
1answer
121 views
Update ranking on table
I have two tables:
mysql> desc rank ;
+----------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
...
2
votes
1answer
243 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 ...
3
votes
2answers
220 views
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 ...
4
votes
3answers
174 views
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 ...
1
vote
0answers
325 views
MySQL join for multiple child records in a single joined row
I have one master table (teacher) structured like
teacherId Name Class
1 Praveen 10
2 John 9
and having a child table (student) structured like
studentId ...
1
vote
0answers
133 views
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 ...
2
votes
2answers
276 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 ...
5
votes
2answers
91 views
mysql join by 2 ways - how it works? - which gives performance difference
I had 2 different ways to query the content which showed performance difference when executed..
The 1st way is
EXPLAIN select SOME_COLUMNS
from
( select *
from A
where CONDITION
) p
...
1
vote
2answers
256 views
Count consecutive null rows from a joined table
I have the following tables:
members:
----------------------------------------------
| member_id | member_name | member_join_date |
----------------------------------------------
events:
...
1
vote
2answers
73 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 ...
2
votes
3answers
653 views
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 ...
2
votes
1answer
293 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 ...
1
vote
1answer
126 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 ...
1
vote
1answer
383 views
Optimizing multi-table left joins
I have four table which I am trying to join together.
Table event
+------------+------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
...
2
votes
5answers
531 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 ...
3
votes
1answer
228 views
Build a three table join with a recusive table in the middle?
I have three relevent tables: Parts, PartGroup, and MarkupGroup.
Parts is simple.
PartID artificial primary key
Part part number
PartGroupID Foreign key
sample data:
1 ...
3
votes
1answer
1k 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:
+--------------+--------------+------+-----+-------------------+-----------------------------+
| ...
0
votes
3answers
457 views
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 ...
3
votes
3answers
414 views
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 ...
9
votes
2answers
1k views
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, ...
1
vote
1answer
243 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 ...
0
votes
3answers
161 views
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 ...
1
vote
2answers
251 views
LIMIT a query Postgresql
im doing this query and it gives me multiple hits because of each assetid may contain many vb.title, how can i limit the result to only show 1 hit for each assetid?
'select DISTINCT v.id,
...
2
votes
2answers
104 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 ...
2
votes
1answer
132 views
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 ...
0
votes
1answer
214 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 ...
2
votes
1answer
294 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: ...
1
vote
1answer
288 views
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 ...
1
vote
2answers
463 views
Table orders regarding Nested loop join in DB2
First I would like to cite the existing post Table order in Join Query
so the author is saying that the table order really doesn't make things(result, access plan)different. I have doubt on this ...
1
vote
1answer
454 views
Really slow DISTINCT ON query with multiple joins
Originally posted:
http://stackoverflow.com/questions/11173717/expensive-query-on-select-distinct-with-multiple-inner-join-in-postgres
The songs table has only about 4k rows, posts and stations have ...
1
vote
3answers
56 views
How can I query to do this?
I have 2 tables, in feeds I have my feeds and (feeds.ID) is the primary key. second table is items. and feeds.ID is realted to items.feed_ID, so with a simple inner join i can extract the data of each ...
2
votes
2answers
2k views
forcing Oracle to use hash join for a subquery
I have a query that looks like
SELECT *
FROM table0
WHERE id IN (SELECT id FROM table1 JOIN table2)
Oracle is choosing to join table0 with the result of (table1 x table2) using nested loops and ...
1
vote
1answer
266 views
Merge multiple table output but indicate which tables the records came from
I have an application with a function that uses a stored procedure (SQL Server 2008 R2) to pull in and arrange data from one table. Now, I’ve been asked to make it pull from two tables, but it’s not ...
2
votes
1answer
360 views
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; ...
5
votes
2answers
248 views
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 ...
1
vote
1answer
397 views
Combine column from multiple rows into one row in SQLITE
I have a sqlite-database with the schema
Articles
Id
Name
Tags
Id
Name
ArticlesTags
Id
ArticleId
TagId
I´m trying to query for Articles.Name and a LIST of tags. Basically what I would want ...
1
vote
1answer
36 views
Linking table or column key
Simple structure:
have a table PAGES - which stores information about specific landing pages
working on developing a GROUPing concept for the pages, where we are saying that a page may or may not ...
2
votes
1answer
111 views
Rewriting a query and eliminating subqueries
I have the following query :
SELECT ws_id, n50, num_singletons, num_segments_less_100, kmer, num_all_reads, number_bases_in_contigs,
num_bases_in_singletons
FROM stats_assembly WHERE ws_id IN (
...
3
votes
1answer
313 views
How to order query results by tag weight in IN('tag1', 'tag2', 'tag3')
Consider a simple query as
SELECT * FROM posts
JOIN tags USING(post_id)
JOIN tag_map USING(tag_id)
WHERE tags.tag IN('tag1', 'tag2', 'tag3')
tag_map is a many-to-many relationship between tables ...
1
vote
1answer
1k views
What joins are available in Informix 9.2?
I'm testing some queries with an old version of Informix (9.2.1) and can't seem to execute even the most basic queries containing RIGHT OUTER JOIN or FULL OUTER JOIN. Tried several variations (RIGHT ...
