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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2
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2answers
172 views

Slow subquery in SELECT statement

Having tried many different methods, I can't get my query taking shorter than 40 seconds to run with a dataset of ~11000 rows. The table is a list of hotel bookings, containing (most relevant) ...
1
vote
2answers
113 views

Select highest id of each type in mysql

I am creating a database that keeps track of backups on our various servers. The query that I am using actually seems to work for the most part. The only issue is that it isn't getting the highest ...
0
votes
2answers
42 views

Which query performs better when searching a row where a column has maximum?

Consider a simple table for example purposes: person(name varchar, age int) I have a task to retrieve the oldest person. Which query is better in general for such problems? Query 1: criteria with ...
0
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2answers
55 views

Delete the second record where a user has two records

I have a simple database scheme, which due to previously being badly set up has numerous duplicate records. record_table |--------------------------------------------------------| | id | subid | ...
0
votes
2answers
71 views

Using subqueries in delete query

I have a table candidate. It contains two columns name and roll. The values in all three rows of data are AA and 10. Now I want to delete only the second row. How can I do it?
4
votes
1answer
60 views

Changes access method for non-correlated subquery

Oracle 11g R2 Unfortunately our application has per row security "features". We have a query that looks about like this: Bad, slow: SELECT someRow, someOtherRow FROM bigTableA a WHERE EXISTS ( ...
3
votes
1answer
86 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). ...
2
votes
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` >= ...
1
vote
1answer
28 views

MySql LIMIT + JOIN is stopping data from being returned?

I originally posted this question on stackoverflow, but then remembered there's a stackexchange specifically for databases! I've got two tables and am trying to return all profiles that are assigned ...
1
vote
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 ...
0
votes
1answer
77 views

Why are correlated subqueries sometimes faster than joins in Postgres?

This relates to the dataset described in Postgres is performing sequential scan instead of index scan I've started working on adapting the import logic to work with a more normalised schema – no ...
0
votes
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 ...
0
votes
1answer
40 views

Passing filter params to a sub query

I'd like to create a view from the query below, but the query contains a sub query which I need to apply a filter to (the place is marked with a comment). I'm wondering if it's possible somehow to ...
0
votes
1answer
67 views

Using a subquery in a LIKE statement

I need to write a subquery inside a LIKE statement. This subquery would return me a word that I need to find in the middle of a sentence (that belongs to another field). Is it possible? This is how ...
0
votes
1answer
101 views

on every row on SELECT Query must lookup to other table

I'm working on Login/Logout System and I'm facing this problem regarding on SELECT Query. I have 2 tables namely dtr_tbl and shift_tbl. In dtr_tbl are the logs of the user(login/logout time details) ...
0
votes
1answer
34 views

Pick up the name of the column by two diff column in single table

Thank you guys in advance! i am desperately need to display my data in this way, My database structure is, Column idcat, parent_id and child_id is sharing single column name, catname. I tried ...
0
votes
1answer
29 views

Querying All Records of All Users who have any instance of purchase behavior in their history

I am trying to write a query that shows me all user ids that in any instance of usage have a particular type of "purchase credit" associated with their account. I have one table, "users" that shows ...
0
votes
1answer
66 views

Stacked Left Joins or Left Join inside a Subquery?

OK, this is a fun one. Designing a database for a gaming system. I have 3 tables that are relevant for the query I'm trying to work on right now. character_skill_log with the relevant fields of id, ...
0
votes
1answer
174 views

Subquery on timestampdiff only allows for 1 result, how do I scale this for all results?

I'm currently writing up a query which is meant to output data to show curves of power profiles, and I'm facing a slight problem. So far, I've managed to do this: select datetime, PLANT_STATUS, ...
0
votes
1answer
77 views

How do I count and order by unique entries?

I have this: SELECT tblClient.[Printed Name], tblClient.[Address 1], tblClient.[Address 2], tblClient.City, tblClient.State, tblClient.Zip, tblClient.Phone, tblClient.[Email Address] FROM tblClient ...
0
votes
1answer
272 views

Need some advice creating this complex view

I need to create a view or query in MySQL to obtain if product has one or more product_detail. This are the create sentences for tables: CREATE TABLE IF NOT EXISTS `stock` ( `product` INT NOT NULL, ...
-1
votes
1answer
48 views

Alter - Subpartition a partitioned table

I have a table which is partitioned by RANGE on DATE key CREATE TABLE T1 DOC_ID VARCHAR NOT NULL. STATE VARCHAR ... DOC_DATE ... PARTITION BY RANGE (DOC_DATE)( PARTITION feb16 VALUES LESS ...
-2
votes
1answer
1k views

postgres: how to use subquery correctly?

I have the following query CREATE TABLE test_buffslip AS SELECT ST_INTERSECTS( (SELECT ST_Buffer(geom, 0.005) FROM segments where class = 7) ,geom) FROM segments; resulting in ...
2
votes
0answers
41 views

Classification of Subqueries?

Just trying to wrap my head around the use of subqueries. Is it correct to say that they come in three main categories: Scalar: returns a single value Table-valued: Returns a table, to compare or ...
2
votes
0answers
75 views

Spatialite: use of virtual spatial index for distances

I'm currently learning to use spatial access methods for query optimization. I'm going through the examples in spatialite cookbook and got stuck in here ...
2
votes
0answers
1k views

Postgres Case statement not return else value in this query

I'm creating a SQL query with a some nested queries and I'm trying to use the CASE statement but it is behaving weirdly. I've been at it for at least 6 hours without any luck... This is my query at ...
1
vote
0answers
191 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 ...
1
vote
0answers
47 views

Delete using join or using sub-query?

I need to delete rows from a table based on what is present in a temporary table. For me, both of these statements work : DELETE from main_table where `id` in (select `deletable_id` from ...
1
vote
0answers
164 views

Problem forming a query with subqueries in design view? (MS Access 2010)?

I just started a new job as a dbase admin intern, and due to the database being very large, it is better to do queries in design view, rather than hardcoding the sql. That being said, I cant seem to ...
1
vote
0answers
348 views

Amazon Redshift: “*SELECT* 1” vs. volt_dt_0 vs. volt_tt_51343b6aa3bd4

I've noticed subqueries in Amazon Redshift can be represented in the explain plan in 3 separate ways: -> XN Subquery Scan "*SELECT* 1" -> XN Subquery Scan volt_dt_0 -> XN Seq Scan on ...
0
votes
0answers
22 views

Searching a text with space in mySql match against Query

I want to search a text in mysql DB with [space] (Ascii 32) as a part of it. But I am not getting the correct result. My MySql Query is: SELECT count(id) as total , MIN(product_price) as ...
0
votes
0answers
34 views

SQL Query with double distinct dates iteration, and start date < my date < final date

I have a kind of rental system database where user can rent an entire house, or just a room of the house. I have a table called offers which has columns id, room_id and a few more. If room_id = ...
0
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0answers
42 views

Moving slow sub-query to With clause

I am trying to optimize this query : SELECT sum(a-alias.s_count) AS count FROM a-table a-alias WHERE ( a-alias.created_at_minute_id >= (floor(extract(epoch from( select ...
0
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0answers
36 views

Need hep with a query to retrive data from realtional database

I am having a database for blog. I want to retrieve posts by specific condition (i.e by location and category). The catch is both location and category are present in a single table called terms. This ...
0
votes
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
votes
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
votes
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
votes
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 ...
0
votes
0answers
97 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. ...
0
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0answers
33 views

subquery in set clause retrieving different values

I want to update the column "kstplcode" using different values coming from column warehouse except the value "main" with their corresponding delivery numbers. I've tried this code but the set clause ...
0
votes
0answers
52 views

Smallest unique string among multiple columns

Somewhat similar to the Largest Common Substring (http://en.wikipedia.org/wiki/Longest_common_substring_problem) I'm trying to find the smallest unique string from a table. In some tables, its just ...
0
votes
0answers
87 views

Indexing on cached data from related table using triggers — Is there a better way?

Edit: Schema details per request from Aaron Betrand -- I'll break the schema down to the relevant fields of the two tables. Orders (ID int IDENTITY, Status char(1)) Services(OrderID FOREIGN KEY ...
0
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0answers
31 views

Subquery optimization

I was reading through this article - http://explainextended.com/2009/09/18/not-in-vs-not-exists-vs-left-join-is-null-mysql/ I am working with an existing design. What I want is to be able to select ...
0
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0answers
105 views

Multiple subqueries performance issue

I have a query that collects customer data. I select a lot of correlated data from different tables. I want to have only ONE result row for each customer. The query looks like that: SELECT c.Id ...
0
votes
0answers
5k views

Multiple SELECT subqueries in an INSERT statement in a stored procedure

So I had the following (genericized), which works just fine for me (barring errors in making the example generic) : DELIMITER // CREATE PROCEDURE stored_proc(IN val1 INT, IN date1 DATETIME, IN date2 ...
0
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0answers
228 views

Latest of group in subquery is bottleneck, how to optimizing query?

See Original question I'm fetching the activity data for the latest activity for each company as part of a bigger query. I've been using the method provided by ypercube, and it works fine, but I find ...
0
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0answers
245 views

Unable to send WHERE parameters to subquery

I have the following problem (in PostgreSQL in combination with PostGIS): I have the following nice query who clusters multiple records. Although it uses PostGIS function, my problem is not PostGIS ...
0
votes
0answers
50 views

subqueries with select

This below query works as expected: SELECT reports.* FROM reports INNER JOIN units ON units.id = reports.unit_id WHERE reports.unit_id IN (1111, 1112, 1113) ...
0
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0answers
314 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
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0answers
547 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 ...