Questions tagged [join]

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

Filter by
Sorted by
Tagged with
0 votes
2 answers
45 views

Is it a good idea to join data from two different databases?

I am building an application that requires a lot of tables in one database and while the joining and aggregation of data is really nice and seamless, I am starting to wonder if I am creating too many ...
jaffer_syed's user avatar
0 votes
1 answer
50 views

UPDATE & SELECT & INNER JOIN combined (SQL92) — How?

I have two tables with the following columns: Table1 id Sort dou and Table2 id_Table1 Sort and I need to read all values of Table1.Sort where Table1.dou = 1 and write them into Table2.Sort, into ...
Gary Czychi's user avatar
0 votes
0 answers
16 views

Dynamically selecting a table in a query based on result from joined SELECT

I have seen many examples but they don't match with my special case (I know... everyone's case is a special case :D ) I have to match values from different tables, some of which are named after the id ...
jprealini's user avatar
  • 101
2 votes
2 answers
215 views

Ignore duplicate rows in a join - and take only one of them

In MySQL I have tables, simplified as follows: companies (id, name, rank, trade_sector_id) orders (id, company_id, paid, subtotal) trade_sectors (id, label) companies_notes (id, company_id, notes) I ...
Ade's user avatar
  • 123
0 votes
1 answer
18 views

Join 1 row out of multiple 1:1 tables and return as array of json objects

I have a database structure like so (in Postgres): An entity has a list of actions associated with it. Each Action has one associated row out of all action-specific tables. Each of these action types ...
Gmanicus's user avatar
0 votes
1 answer
38 views

Help with SQL Query: Is there a cost-efficient way to join multiple tables to one main table?

I have a main table set up like this: id table_to_join table_item_id 1 products 123 2 products 577 3 products 344 4 products 1230 5 images 14 6 images 42 7 video 555 8 products 400 9 video 9 ...
peppy's user avatar
  • 33
0 votes
2 answers
40 views

Delete all rows if input parameter is 0 otherwise delete only those entries which match the input param

I have a stored proc which is receiving id as input. If the id which is received is 0 then we need to delete all the rows otherwise we need to delete only those rows which matches the input id. I can ...
Himanshuman's user avatar
3 votes
5 answers
1k views

Optimizing SQL Server Query When Joining Tables on DATETIME column

I am working with SQL Server and I have two tables, table1 and table2. Both tables have a DATETIME column denoted as dt. I need to join these tables based not only on certain conditions but also to ...
Fajela Tajkiya's user avatar
2 votes
2 answers
119 views

Column isn't in GROUP BY error on join query

I'm trying to get best selling products. Tables CREATE TABLE `items` ( `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `price` ...
Mohammad A. Apu's user avatar
-3 votes
1 answer
75 views

subquery vs join which is better [closed]

SELECT * FROM table1 WHERE t2id in ( SELECT id FROM table2 WHERE t3id = (SELECT id FROM table3 WHERE id = '1') ); SELECT * ...
guradio's user avatar
  • 97
1 vote
1 answer
60 views

PostgreSQL: Sum filtered items in a one-to-many relation

I have events and sessions associated with them in a one to many relation. I want to make a query to get the amount of past, happening and upcominng events. Past events have no active sessions ...
Tomás Mendes's user avatar
1 vote
2 answers
48 views

How to optimize SELECT COUNT with LEFT JOIN?

I have a MariaDB 10.5.10 database, with a table activity made of 150,000 rows. it holds: an id field (integer, primary key) a tenant. There are about 85,000 rows with tenant = 12 an activity_type (...
bfredo123's user avatar
  • 113
0 votes
0 answers
34 views

How to join matching Date fields as intervals?

Let say I've a table with a list of id/year/month (two years + 24 months for semplicity here): Code Year Month MAT000000001 2022 1 MAT000000001 2022 2 MAT000000001 2022 ...
markzzz's user avatar
  • 221
0 votes
1 answer
27 views

Joining per group in group by

I have a table with some animal sightings data where each sighting entry has a region field. There can be 0 to many entries per region per day. I need to create a query where there is one row per day (...
Christopher Lang's user avatar
0 votes
1 answer
211 views

Left Join with only one of multiple matches in the right table

I have a database, where every entry may have multiple names, therefore I made a name database. While all names will be displayed otherwhere I need a list of all main entries with one representative ...
Benito's user avatar
  • 1
0 votes
1 answer
41 views

Different index selection and join strategy between QA and Prod environments in PostgreSQL

I have encountered a scenario where the same query on a PostgreSQL database is exhibiting different index selection and join strategies between the QA and Prod environments. I'm trying to understand ...
sujeet's user avatar
  • 213
0 votes
1 answer
35 views

Compositing ordered SQL tables without Joins

I'm currently exploring some weird ways of doing things and was wondering if anyone has any experience with the following methodology. Background I have a handful of NF3 tables, and NF1 source data. ...
Vocoder's user avatar
  • 117
0 votes
2 answers
20 views

SQL multilevel join how to add a where condition

I have the following SQL query SELECT r.id as id, reports.Timestamp as reportTimestamp, reports.Latitude as reportLat, reports.Longitude as reportLng, FROM Requests r LEFT ...
Matt Welander's user avatar
0 votes
0 answers
159 views

MySQL indexes on temp tables

I am trying to perform joins between two temporary tables, creating an index on the join key for each temp table. However, when I EXPLAIN the join, the row estimates always seem to come out vastly ...
im123's user avatar
  • 1
0 votes
1 answer
34 views

Join two tables with similar columns

I hva two tables as is: Table univers: client commercial Axel Tony Mike Jhon Chris Jhon Table transactions frclient toclient commission Axel NA 10 Mike NA 8 NA Mike 15 Axel NA 4 NA Chris 5 ...
COPEGUEST's user avatar
0 votes
0 answers
23 views

How to Join two tables with SUM in SQL server [duplicate]

i have 2 tables 1.registros 2.servicios what I wanna have is this: id,nombre,apellido,direccion,telefono servicios_pedidos of table 1 + sum of table 2 servicion.precios with table 1 registros.[...
rodrigo 's user avatar
1 vote
2 answers
44 views

How to leave only the rows with an timestamp difference with an interval greater than a parameter

I have a Postgres table with timestamps as entries. From this table, I would like to calculate a new one where there are no consecutive entries with a timestamp difference shorter than 400 ...
eddie_jung's user avatar
0 votes
1 answer
13 views

Issue in Retrieving data from Table when it is having more than 1 records for 1 ID

I have a table ABC and it has 5 columns and now I need to find such records in the table for same ID value where the value in columns C is 0 in all the cases. Solution please.
Nitin Punj's user avatar
0 votes
4 answers
102 views

LEFT JOIN 3 tables NULL rows not as intended

Scenario - a sailing event with entrant categories. I am a volunteer and I am struggling to get a result table for each entrant listing their selection (or NULL if none chosen) for each category. ...
Chris H's user avatar
0 votes
1 answer
94 views

Joining Columns with different character set

I am joining two tables on varchar columns having CHARACTER SET utf8 COLLATE utf8_bin and one with CHARACTER SET latin1. Indexing is not working when i am joining these two tables on this column, I am ...
Manish Kumar's user avatar
0 votes
1 answer
23 views

update row with age calculation with DOB in related table

SQLite database with a table "events" with a columns events.eventDate, events.ageAtEvent and events.foreignKey_participants, and a table "participants" with columns participants....
Stam Kapetanakis's user avatar
0 votes
1 answer
30 views

Select tables data with sum of other tables

I am very new on MySQL DBA and i searched but i am not clearly understanding inner join with sum. user table: id, username, locationid history table: id, username, locationid, spent Example user ...
Imran Ahmed's user avatar
0 votes
1 answer
70 views

SQL Server 2014 Cardinality Estimator estimate final number of rows after OUTER JOIN is less than number of rows from initial table

I have a [SQL query] for SQL Server 2019. It works fine with option (USE HINT ('FORCE_LEGACY_CARDINALITY_ESTIMATION')) and very bad without this hint. I found out, that SQL Server 2014 Cardinality ...
Андрей Ерёмин's user avatar
2 votes
2 answers
70 views

Join order and nullability

I am asking this question in the context of using a Postgres database, although I would imagine it would apply to most SQL databases. When working with the results of a database query inside a ...
Daniel Rearden's user avatar
0 votes
1 answer
53 views

ORA-12015 materialized view complex query error with simple join two table

I have 2 simple table which has columns like : table1 : "OBJECTID" NUMBER NOT NULL ENABLE "OLCEK_ID" NUMBER(*,0) table2 : "OBJECTID" NUMBER NOT NULL ENABLE i created ...
CartWheel's user avatar
1 vote
1 answer
76 views

Worst performance multiple left join big tables after restore DB

Problem Database: PostgreSQL 13.8 (Debian 13.8-0+deb11u1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit After migrate from DigitalOcean to strong Dedicated Servers ...
M. Garbarczyk's user avatar
1 vote
1 answer
64 views

What's the fastest way to query multiple tables at once where each table represents one year of data?

I'm developing an web app based around a database with multiple decades of data with multiple schema changes over the years. Each year of data is released as a zip file containing CSVs named table1....
Tyler's user avatar
  • 11
0 votes
2 answers
83 views

How to fill a join table with one SQL statement in MySQL?

I have these tables CREATE TABLE users ( id INT NOT NULL AUTO_INCREMENT, username VARCHAR(15) NOT NULL UNIQUE, password VARCHAR(200) NOT NULL, name VARCHAR(...
Sergey Zolotarev's user avatar
0 votes
2 answers
64 views

Join and use most recent data if NULL

Table WSHOSHO SELECT * FROM WSHOSHO; Table RRP SELECT * FROM RRP; Join to illustrate issue The results of this join can be used to illustrate the issue: SELECT * FROM WSHOSHO RIGHT JOIN RRP ON (...
dharmatech's user avatar
1 vote
1 answer
19 views

Listing Entries from Table1 which do not appear in Table 2

Currently I am working with 2 tables... one table consists of jobs carried out and also the invoice number... there could be multiple jobs for a customer on the one invoice... the table might look ...
PaulMcF87's user avatar
  • 167
1 vote
1 answer
62 views

How I can retrieve the latest records without using lateral join?

I have the following database: create table "client" ( id SERIAL PRIMARY KEY, name VARCHAR NOT NULL, lastname VARCHAR NOT NULL ); create table store ( id SERIAL PRIMARY KEY, ...
Dimitrios Desyllas's user avatar
1 vote
1 answer
69 views

Mismatch between the total number of rows in a sql join

When I join entries from the points table (n = 34, 436) to the mid_pts table (n=1.98 million) the total number of rows of the table_joined is n = 26,016. However, when I add the unjoined_pts table of ...
MJM's user avatar
  • 123
1 vote
1 answer
398 views

Optimal join for joining facts with scd-type-2 dimension for aggregation/reporting

I have a fact table and an scd-type-2 dimension table. I want to produce sales report by region and year. I have working solution with a query that joins them for reporting purposes. When I run the ...
Kashyap's user avatar
  • 149
0 votes
1 answer
33 views

Postgres join as inner json

Just trying to do a simple inner join as json. model posts (author is fk to profiles.id) id author title ... profiles id displayName ... Trying to do a simple join so that: select * ...
Jonathan's user avatar
  • 143
0 votes
1 answer
85 views

MySQL query takes too long to execute

I'm working on an IOT based application for which I'm storing time series data in MySQL. I have two tables in different databases as follows: describe fo_data.device_data; +-----------+----------------...
mrid's user avatar
  • 101
2 votes
2 answers
108 views

Straightforward inner join is slow despite using indices and ref/eq_ref types

I have a couple moderately-sized MySQL 8.0.30 InnoDB tables: models - 1,000,000 rows activations - 10,000,000 rows A fairly simple INNER JOIN takes about 500ms, which seems like a lot (is it?). This ...
mgiuffrida's user avatar
0 votes
0 answers
27 views

how to make joins on different tables based on the data retrieved, with TimeScale/Postgres

Here is a simplified version of the problem I'm trying to solve: Table A with id and some data: id, data A01, xxxx A02, xxxx ... Table B with id and some other kind of data id, data B01, xxxx B02, ...
Thomas's user avatar
  • 273
1 vote
1 answer
153 views

Find duplicate values by joining tables SQL server

Finding the duplicate values in the 'Item_Sales_Detail' table as NULL rows in the 'Sales' and 'Item' tables by joining three tables. 'Sales' table (ID is primary key) ID Invoice Date TotalAmount 10 ...
Mohammad Bastan's user avatar
0 votes
0 answers
88 views

Redshift / Postgresql query multiple tables faster than Natural Full Join

I have been given a requirement to query 8(+) different Redshift tables and return some of the fields where email = provided email address. Current implementation: (select product_name, email, ...
AylaWinters's user avatar
0 votes
0 answers
27 views

Avoid Duplicates Record

SELECT DISTINCT log.employee, log.attendance_date , case when ch.log_type = 'IN' then TIME_FORMAT(ch.time,"%H:%i:%s") end as attend_time , case WHEN ch.log_type = 'IN' THEN CONCAT(...
hisham_y's user avatar
0 votes
0 answers
20 views

In rest api how to get parent_id have child_id in same database using node.js and used at regressive function

{ "error": false, "message": "Data fetched successfully", "exam_format": [ { "id": "b2a9f30f-04bf-4735-b293-...
Backiyanathan M's user avatar
-1 votes
1 answer
632 views

Retrieve all data from an inner join with duplicate column names in MySQL

I have a database with tables for "users" and "profiles". Every profile links back to a user. I would like to do an inner join where I am able to retrieve a set of profiles that ...
Eric Johnson's user avatar
0 votes
1 answer
40 views

MYSQL: Return a predefined value if result of join is null

Before all, sorry my very bad english level. Here's my problem. If i have two tables: 'Products' |id | product | |---|---------| |1 | "Fork" | |2 | "Spoon" | |3 | "Knife&...
Matt Ross's user avatar
0 votes
0 answers
30 views

Joining Two Tables via JSONB column (date)

Given the following data: create table datas (id int, data jsonb); insert into categories (id, budget) values (1, '{"2022-07-01": {"budget_amount": value1, "some": &...
RMcLellan's user avatar
-1 votes
1 answer
53 views

Add Some custom Text at the place where value is null in the join?

I want to join two table in such away that If there is no value against first table entry in the second table then it should fetch that row but insert some custom text in that row. Is there any ...
Manii's user avatar
  • 133

1
2 3 4 5
40