SQL term used to describe when a `SELECT` statement is used as part of a larger SQL statement. The larger statement may be DML and is always found within brackets or parenthesis.

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71 views

Return 2 columns from MySQL subquery?

I'm new in MySQL programing and I have one problem. I created this query: SELECT *, topics.createdate AS TopicCreateDate, (SELECT (SELECT username FROM users ...
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1answer
113 views

Subquery can't find column from superquery's join

I'm running into some trouble with SQL: Basically I'm trying to get a result set back that contains a sum of ALL questions asked to employees (grouped by company) and also add the "onetime_items" ...
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2answers
85 views

Effect of where statement in subquery (to get rid of unnecessary join)

Please consider the following query: select * from parent p where p.id in ( select p.id from parent p inner join child c on c.parentId = p.id where p.age > 50 ) Is it safe (in general!) ...
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2answers
91 views

simple SELECT EXISTS takes about two hours to execute

I have mysql server hosted. Now, If I issue simple SQL statement SELECT EXISTS (SELECT * FROM ORDERS WHERE USER_ID='c85bc9f7-704f-418e-98af-a1528622dd42' AND PLACE_ID='2' AND ...
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1answer
36 views

Understanding the given correlated subquery

I am unable to understand how this correlated subquery works on the relation Student={Sid,Sname,marks} Select Sname from Student s1 where (select count (*) from Student s2 where ...
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2answers
88 views

How can i return the max of a sum by each team?

I have a lot of teams and i want to know the maximum of sum total of each team. This's my query : SELECT campaign_id, campaign_identifier, team, campaign_name, ...
4
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1answer
47 views

MySQL query returns different result on second execution

I'm not too familiar with MySQL variables but I'm trying to avoid redundant sub selects while calculating these results. The first execution only returns 1 of the correct calculations. The second ...
2
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1answer
71 views

Join query returning 0 rows - impossible where

My query is performed from a php web request using a PDO prepared statement. My desired output is to list the top 10 brands which have the same transaction id as the 'selected' brand :brand by order ...
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1answer
44 views

Return the lowest value

How do I go about getting the course number (CNO) of all the lowest enrolled by department? For example if math had coursenum 123 and the 0 enrolled, and anoher coursenum 555 with 6 enrolled, it ...
3
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1answer
176 views

Minimizing Page Fetches

I have a complicated database structure and am trying to use it to retrieve Records based on multiple selection criteria from several tables. As a general rule, is it better to attempt to use ...
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1answer
60 views

Single MySQL query with row averages based on conditions

I have problem, where i know how to proceed with multiple queries, but dont really now I Have a table with BP { name: varchar systolic : int diastolic : int timestamp: date } I need ...
1
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1answer
26 views

Help writing a query that select the min column in a group by

I have two simple table CREATE TABLE user ( id INT NOT NULL AUTO_INCREMENT, nickname varchar(35) NOT NULL, PRIMARY KEY (id), ); CREATE TABLE user_service ( id INT NOT NULL AUTO_INCREMENT, ...
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0answers
25 views

How to use COUNT() properly with a 3 table join

I have a database where I have driver details, their assigned routes and their stop locations. For each driver on the database I need to find the location (or locations, as it could be more than one) ...
0
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0answers
35 views

How to pull sales for every single month based on my query below using ORACLE

So I am working on a report right now that pulls customer information, and sales for a particular date range, who used a PROMOTION CODE. My current query pulls all the data I need and gives me a sum ...
0
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3answers
84 views

Select data from single table using Self join

I have requirement to select a data from single table. The requirement is as follows Select data from table which has one value but not another. for e.g I want to select distinct ID which has value 1 ...
0
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0answers
14 views

Microsoft Access Address Book Form Query

I have downloaded the Microsoft Access template for an address book. I am looking at the contact form and it allows you to query the db and pull back a record and all the details in the row. What I ...
0
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2answers
74 views

SELECT fields from table having some conditions

I have two tables 1. Named as t1 2. Named as t2 example of the tables are : t1 : id name 1 one 2 two 3 three t2 : id name 2 five I need to select all the data ...
0
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1answer
63 views

get all the count of sub category from the product table in single query with mysql optimization [closed]

Table structure: CREATE TABLE some_table ( `product_id` int(11) NOT NULL AUTO_INCREMENT, `product_name` varchar(255) NOT NULL, `Product_model` varchar(255) NOT NULL, `product_discount` ...
0
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1answer
52 views

Subquery returned more than 1 value. My WHERE clause needs to remove SELECT statements [closed]

I have a SQL Stored Procedure that is giving issues. I am aware that it is most likely the SELECT statements in the WHERE clause that are returning multiple values. I commented out the WHERE and ...
0
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0answers
23 views

Is it possible to stack similar columns from a subquery and join the other unique columns in one query?

I am fairly new to the sql world and have been struggling with a query. I have two subqueries that are generating tables with two columns. The first table is part # and model_countH. The second table ...
2
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2answers
94 views

Query with WHERE NOT and NOT IN with subquery

MySQL Version: 5.6.27 I am using the following two tables TABLE: oc_product product_id int(11) model varchar(64) tax_class_id int(11) and TABLE: oc_product_to_category ...
4
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2answers
68 views

Join subquery by year and month

I want to collect data from differed tables grouped by year and month. I'm using subquery for each sub data. Using mysql. SELECT YEAR(td.db_date) AS stat_year, job.total_jobs FROM ...
3
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1answer
10k views

Writing a query to find all employee salaries that are higher than their managers

I have two tables with some dummy data. I need to find all employees that make more than their managers. I was led to believe the point of the exercise is to learn how to do subqueries. I can isolate ...
0
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1answer
81 views

MYSQL join on subquery optimization

This is a distilled version of the query that I am trying to run: SELECT * FROM table1 t1 INNER JOIN (SELECT * FROM table2 WHERE foo = 'bar') t2 ON t1.id = t2.id; The above query is incredibly ...
2
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1answer
282 views

Very slow update with subquery (different tables)

I run this query to update "domains" table based on "log" table: UPDATE domains SET domains.mx_collected = 0 WHERE domains.domain IN (SELECT log.mail as domain_name FROM log WHERE `time` >= ...
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3answers
104 views

Updating rows from other rows in a huge table

I have a huge table with items item-id | name | type | extra Many of them are "old versions" of type 0. I have to update the extra field in all new items (same item-id, but type > 0) with the ...
2
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1answer
96 views

MariaDB subquery cache scope and settings

I am migrating an application from MySQL 5.6 to MariaDB 10. One major new feature of MariaDB is the subquery cache. I am trying to determine the expected effect this cache will have on our ...
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3answers
417 views

Slow update on large table with subquery

With SourceTable having >15MM records and Bad_Phrase having >3K records, the following query takes almost 10 hours to run on SQL Server 2005 SP4. UPDATE [SourceTable] SET Bad_Count= ...
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0answers
96 views

Slow mysql query full text search tag database

In the database are ~700k images. Each image has its own tag(s). I want to be able to search images by the tags with a full text search query. The query does exactly what I want but it's very slow. ...
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1answer
52 views

Left join not working with sub-query

I've got table of scores where each entry corresponds to a particular (student, subject) pair. CREATE TABLE score ( id serial PRIMARY KEY, value integer NOT NULL, subject_id integer NOT NULL, ...
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0answers
36 views

MySQL - SELECT Columns from results of another Query [duplicate]

I'm trying to use a dynamic range of columns fetched from another query, specifically I want the results of this query: SELECT COLUMN_NAME as DYNAMIC_COLUMN FROM information_schema.columns WHERE ...
1
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2answers
135 views

Multiple COUNT fields, GROUP BY

I'm trying to group two columns in my MySQL database and show counts for them respectively (as separate columns). Is there a way of doing this or do I have to join two sub-queries? I'm aware of WITH ...
2
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2answers
300 views

PostgreSQL query very slow when subquery added

I have a relatively simple query on a table with 1.5M rows: SELECT mtid FROM publication WHERE mtid IN (9762715) OR last_modifier=21321 LIMIT 5000; EXPLAIN ANALYZE output: Limit ...
2
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1answer
39 views

Problem to select not in

I want to display the values that are between 0 and 10 and dont exist in the current table For example : Field 1 2 3 5 9 8 Result expected: 7 4 The problem is that the column field is a ...
8
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1answer
146 views

How can I get the hierarchical values from the below query?

I have a table named Category which has a column named CategoryID. There is a referencing column in the same table called fParentCategoryID. I need to get all the category IDs and their subcategory ...
10
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1answer
266 views

Why is my SQL Server query behaving differently on UPDATE than on SELECT?

I've written a SQL Server query that updates records to have a sequential number after partitioning on a field. When I run it as a SELECT statement, everything looks great: DECLARE @RunDetailID INT = ...
0
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2answers
241 views

#1093 - You can't specify target table 'R' for update in FROM clause

As an attempt to answer Difference data between adjacent rows UPDATE Visits R SET Duration = TIMEDIFF( ( SELECT ReqTime FROM Visits N WHERE N.ID > R.ID AND N.Session=R.Session ORDER BY ID ...
3
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1answer
83 views

Storing prices with price history and different specificity (global, user group, single user) in MySQL database

I need to store prices with their history. A price can have different specificity. It can refer to a single user (most specific), group (less specific) and product price (global - least specific). ...
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2answers
76 views

How to optimise MySQL query that uses dependent subquery

I have a web app that has a custom feed of images. The image queried are based on whether the users have previously seen the image and ordered by a Hacker News style score. There are only 1000 rows ...
4
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1answer
108 views

Why is the subquery apparently correlated? How to avoid it?

I have a table orders and a table orderpositions. The orderpositions (basically the items bought with the order) are linked via orderid (indexed) to the orders primary key. For a given set of orders ...
3
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2answers
7k views

MySQL: Delete all but last N records

Consider the following table: mysql> DESCRIBE pixels; +---------------+-------------+------+-----+-------------------+----------------+ | Field | Type | Null | Key | Default ...
1
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1answer
70 views

Is it more efficient to union from sub-query or combine two outer queries?

I searched for this but couldn't find the response I needed. So my apologies if this has already been asked. I'm asking in regards to DB2 but I suppose this would apply, generally speaking, to just ...
1
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1answer
148 views

mysql - select random rows with max 3 rows per parent id

I currently have a query that returns a maximum of 3 rows per parent_id. I want to enhance the query to return a maximum of 3 random rows per parent_id. This does not work for me at the moment as it ...
1
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2answers
267 views

Use array expression from subquery in ANY() condition

I have a relatively complicated query with a subquery fetching an array like so: ... ARRAY(SELECT category_id FROM category_schedule_con con WHERE s.id = con.schedule_id ORDER BY category_id) ...
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0answers
190 views

Update row value with a sub-select join

I am trying to update 1 column in all rows in a table to have an appropriate count value. Sadly, the SELECT query I am using won't let me join on a field in update table. The query looks like this ...
0
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1answer
94 views

Subquery returned more than 1 value. please help. i beg for mercy

This is may table. In one column there are daily dates and in the other is a classification. I use this query to count how many registers are in a month and which ones are C or D, but the subquery ...
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2answers
82 views

Optimize query or split in two queries and process result separately?

I have this DB schema: As you may notice already there is no relationship between tables and won't be on the future. If I run the following queries I will get a lot of rows per table: SELECT ...
3
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3answers
2k views

No advantage of using Cross Apply or CTE over inline sub-query

I came across a query like this: SELECT (SELECT COUNT(1) FROM Orders o WHERE i.ItemId = o.ItemId) [C] FROM Items i I changed it to following ;WITH cte_count AS ( SELECT COUNT(1) c, OrderId ...
2
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2answers
55 views

Need some assistance on MySQL Sub query

I have a table in MySQL. The table structure is as follows. id | emp_id | call_start | call_end | call_type -------------------------------------------------------- 1 | 20043 | ...
3
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1answer
139 views

Subquery magic in PostgreSQL

I have a query: update product_product set (write_date, default_code) = (LOCALTIMESTAMP, 'update') where product_tmpl_id in ( select distinct product_tmpl_id from product_template ...