2
votes
1answer
28 views

WHERE attribute having two relation lines in the same SQL

I have a database designed with tree tables: checklist (id, name) tag (id, name) checklist_tag (checklist_id - FK, tag_id - FK) Running this SQL: SELECT cc.id as checklist_id, cc.name as ...
0
votes
1answer
27 views

Query to join three tables

I have three tables which I have to join. I'm not a good SQL writer. Can please sombody help me to prepare this using joins: branches ----------------------------------------- branch_id | branch_name ...
1
vote
1answer
28 views

Merge a table into an existing one

I know how to JOIN two tables as create a new table out of the results, using CREATE TABLE result_table AS ( SELECT * FROM tableA JOIN tableB ). I forgot to include some columns from the JOIN in the ...
0
votes
2answers
32 views

Using a join to return multiple values of the same column?

I have two tables user Rank In the Rank table, I saved rank_id and supervisor_id. In the Rank table, I stored the rank name. The rank_id and supervisor_id are foreign keys from the Rank table. ...
0
votes
1answer
54 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 ...
1
vote
2answers
60 views

Get only the oldest entry in a join

So I have a table bugs |bugid| title| the table is lacking a date column. But when creating a new entry, most likely always a new entry gets created in bugnotes as well saying "bug created" with the ...
0
votes
1answer
41 views

How to simulate a table join on itself?

Let's assume this is my current data: product_number date value 100 2010-01-01 1 100 2010-02-01 1 100 2010-03-01 1 200 2010-01-01 1 ...
1
vote
1answer
13 views

Select the last logged change before a specified time from a change list

I want to get the last change for all issues issue, that was made before a specified end time. I have 3 tables. projects +---+------------+ |ID |project_key | +---+------------+ |1 |bug_tracker | ...
0
votes
1answer
35 views

How to join 3 tables together given 2 many-to-many relationships tables in between?

I have 3 main tables: Person, Publication and Conference and 2 many-to-many link tables in between: person_publication and person_conference I want to join all 3 main tables together (showing me all ...
1
vote
2answers
49 views

Mysql LEFT JOINing same table twice

mysql> SELECT * FROM customers; +----+------+ | id | name | +----+------+ | 1 | Matt | | 3 | John | +----+------+ mysql> SELECT * FROM purchases; +----------+------+-------+ | owner_id | type ...
0
votes
1answer
25 views

Optimizing a query so MySQL will use the indexes for the joins

Some context: migrating some data from a 3rd party cloud MongoDB platform service into MySQL. Wrote a query but it's very slow. Here's the query: SELECT Table1.*, (long list of fields for each ...
1
vote
1answer
34 views

Joining Three Tables by using IDs as Foreign Keys

I'm starting out with learning MySQL and so far I realized I need to JOIN three tables. The three tables are Users Groups Members There is a list of users, a list of groups that users can join, ...
0
votes
1answer
48 views

Join 3 tables returns too many results [closed]

I have 3 tables: users, posts, videos. The last 2 tables have user_id that associate with users.id (first table). The problem is that when I try to run inner join query and return all posts and ...
3
votes
1answer
37 views

Doing a join to search geolocation points in zones

I have a series of geolocation points in a table, and a series of "zones" in another; I'd like to do a join to identify which zone each point belongs in (if at all.) Points table looks like: ...
0
votes
1answer
37 views

Problem JOINing three tables

I want to show all the categories and the items inside that each category which should store in items_this_category. Note, I have created an associative table item_categories because one item can be ...
1
vote
1answer
67 views

Performance issues when extracting scatter plot data

First off: Sorry for the title, couldn't think of anything better. Feel free to change it though. Ok, assume I have the following table: ...
0
votes
0answers
47 views

Very slow inner join

newby on mysql so help needed I created a my sql query, on their own they run fast but when I enter the inner join it runs forever. i did index theres id tables but no result in speed. here is my ...
0
votes
0answers
63 views

MySQL: Is it possible to join a virtual table with itself?

I am not sure if 'virtual table' is the correct phrase. I am instantiating a table X like so: SELECT * FROM ([some select subquery]) X and I would like to cross join that table with itself several ...
1
vote
1answer
105 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 ...
3
votes
1answer
98 views

MySQL - GROUP_CONCAT returns duplicate data, can't use DISTINCT

I have a normalized database and I'm trying to return data from multiple tables using JOINs and GROUP_CONCAT. Problem: Rows are being duplicated with GROUP_CONCAT. I can't use DISTINCT because some ...
0
votes
2answers
67 views

JOIN on variable number of columns

I have the two tables courses AND something_about_courses: courses course_code course_session course_type something_about_courses course_code course_session some_description To ensure that I ...
0
votes
1answer
64 views

MySQL query using left join on two inline views not returning rows without values in second view

For some reason when I execute the code below I'm only getting results back that have sku in both views. I thought this should give me everything in the first view and add the content from the second ...
0
votes
1answer
46 views

limiting rows in joins

So I have this problem with one of my queries. The query is meant to get data from table patients and join the table patient_nurse, then table nurses to it. The patients table is as follows id | ...
0
votes
1answer
73 views

MySQL: LEFT OUTER JOIN within reason

What I'm attempting to do is LEFT OUTER JOIN a table, but I only want the last inserted record of the joined table to affect the results. Currently each table row within the joined table seems to be ...
0
votes
1answer
68 views

mysql directory grow to 246G after one query, which failed due to table is full

I was trying to run the following statement with the hope to create a join of two existing tables. create table CRS_PAIR select concat_ws(',', a.TESTING_ID, b.TRAINING_ID, a.TESTING_C) as k, ...
1
vote
1answer
90 views

Innodb buffer pool and multiple joins

assume we have 1 Billion records and want to store them in One or Three tables by post_type. post_id -> primary key post_type -> ( page, group, user ) user_id -> index date -> ...
1
vote
1answer
408 views

MySQL: NOT EXISTS vs LEFT OUTER JOIN…IS NULL

Is NOT EXISTS or LEFT OUTER JOIN...IS NULL more efficient for finding records in one table that aren't in another? Specifically, I'm trying to figure out which of the two queries below is better: ...
6
votes
3answers
457 views

Can someone explain why left joining two views in mysql is so slow?

Here is a question I asked yesterday - http://stackoverflow.com/questions/22180727/left-joining-two-views-is-slow. I got a good answer that helped me but I don't understand why the LEFT JOIN is so ...
0
votes
0answers
53 views

Selecting posts, user details and votes from 3 SQL tables

I have a user table with id, username, email etc.. post table with id, uid (user id), content etc and vote table with id, uid, pid (post id), vote (ENUM : '1' and '-1'). In the vote column of Vote ...
0
votes
2answers
83 views

Select * on inner join with common columns

I have 3 tables (mysql db) on which I want to do an inner join. The problem is that these tables have common columns. I know I could use aliases to differentiate them (select A.x as Ax, B.x as Bx, C.c ...
0
votes
1answer
65 views

Can't get rid of “temporary; Using filesort”

I can't get rid-off "temporary; Using filesort" when ordering columns from the second table explain SELECT * FROM post JOIN post_plus ON post_plus.news_id = post.id ...
0
votes
0answers
101 views

USING to join multiple tables with same field

I have 4 tables, each with a common field QuestionnaireId. I am wondering if there is any difference in output or performance difference between using USING on the field in each join or by specifying ...
0
votes
1answer
60 views

Ask about Inner Join & Union

i want to ask about my script this is doesn't work. i need to help ! SELECT A.*,B.mat_nama,C.mats_nama FROM pengeluaran AS A INNER JOIN(material AS B) ON(A.mat_id = B.mat_id) INNER JOIN(mat_satuan ...
0
votes
1answer
76 views

Get the value of one attribute from the reference key of another table?

I have two tables named as ps_order_detail and ps_product_lang in MySQL. I want to get the product name from one table whose reference key is in another table. I have two tables. First the ...
0
votes
0answers
40 views

MySQL - query join returning zero recs from table with data

I've provided a file that has the table structure and some sample data that I'm working with. I don't understand why I'm getting nulls from a joined table, where there is data. Here's my query ...
0
votes
0answers
106 views

Alternatives for subquery

There are three tables: product_hits, products, and product_subcategory_map. I want to count the number of product_hits and for each product. There could be more than one subcategory in the ...
0
votes
0answers
117 views

Select Foo object without any specific Bar events

Consider two tables: Foo: id INT, name VARCHAR Bar: id INT, foo_id INT REFERENCES Foo(id), event_type VARCHAR DEFAULT NULL, event_duration INT DEFAULT NULL Each Foo item can have ...
0
votes
1answer
55 views

MySQL: join query

I've got the following two tables: mysql> DESC domains; +-----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra ...
0
votes
1answer
59 views

Would it be better to do a sepparate query instead of a left JOIN?

Only a couple of rows is returned when not using LEFT since there isn't always data in the associated table - recipe_preparation. This is one of a couple of tables with the same "issue". SELECT r.id, ...
1
vote
2answers
98 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) ...
0
votes
0answers
77 views

Alternative to TEMPORARY tables capable of re-opening in a query?

I use TEMPORARY table for calculation of temporary data, but TEMPORARY tables in mysql has a big limitation, which made it useless for me. A table cannot be re-opened in a query. This mean I cannot ...
0
votes
2answers
70 views

Is my JOIN syntax not valid? And have I understood JOIN correctly?

I've been reading up a bit regarding JOINs. And i just noticed that I've been writing the syntax a little bit different. Although I don't think there's any problem with it, I would like to hear your ...
0
votes
1answer
144 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 ...
1
vote
1answer
762 views

UPDATE a column by COUNT of another table

It might be a naive question, but what is the difference of these two queries and which is preferred? UPDATE table1, (SELECT id,COUNT(*) idcount FROM table2 GROUP BY id) AS B SET table1.Freq = ...
0
votes
1answer
71 views

Get all items from list table which don't have a successful log entry for 'sent' in log table

How might one retrieve items that when joined either don't have a specific field (sent), or if they do have that field (sent) then they have an additional field (failure_reason) as well for every sent ...
1
vote
2answers
338 views

Full outer join does not work for two small tables, error 1064

folks. I am currently exploring the capabilities of MySQL while doing simple exercises with diverse queries. I was reading the following article that explains how table JOIN works: ...
1
vote
1answer
433 views

Using OFFSET in a large table by a simple sub-query

The slow performance for using OFFSET in large table has been widely discussed in various blogs, and the most efficient way is to use an INNER JOIN as SELECT * FROM table INNER JOIN ( SELECT id FROM ...
1
vote
0answers
53 views

join performance, index vs. index+foreignkey

I'm using an orm framework that handles data (and its integrity) on top of mysql. So far I ignored foreign keys because the orm handles that just fine. I recently read that foreign keys can enhance ...
1
vote
1answer
2k views

Select records in one table but not in another, when the second table is not matching on primary key

I have two tables from which I need only the results that appear in one table (list) which do not appear in the second table (cardinal). The list table's primary key is sku, and the table has a ...
1
vote
0answers
116 views

MySQL join query indexes

After recently discovering the MySQL feature to log queries that aren't using indexes, I've been chasing these down in a large app, looking for places to improve performance. There is at least one ...