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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11
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1answer
263 views

Why does subquery use parallelism and join doesn't?

Why does SQL server use parallelism when running this query which uses a subquery but it doesn't when using a join? The join version runs in serial and takes around 30 times longer to complete. Join ...
0
votes
0answers
113 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 ...
1
vote
1answer
1k 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 = ...
1
vote
1answer
556 views

How to get MySQL to iterate a subquery in an aggregate select?

Because the vocabulary describing what I'd like to do can be so disparate, I haven't had any luck figuring out why MySQL 5.6 is doing what it does. Consider the following two simple queries: #1 ...
2
votes
0answers
478 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
1answer
605 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
1answer
177 views

How to UPDATE a column by COUNT of FK from another table?

How to extend this query for the entire table, to update all ids? UPDATE table1 SET number=( SELECT COUNT(*) FROM table2 where id=1 ) WHERE id=1 id is the PRIMARY KEY in table1 and FK in table2. ...
0
votes
1answer
90 views

Combine results from two queries?

I need to combine the results from two queries into one result set and order them altogether. This is the working, raw SQL code I have: SELECT * FROM ( SELECT t1.id AS entity_id, ...
0
votes
1answer
161 views

Optimizing multiple MySQL sub-queries and joins for multiple runs

The query (below) that's running is taking ~0.6 sec which normally would be fine but it gets run almost 1300 times for different custids. How can I make it run faster? Setup: Mac OS X 10.7.5 MySQL ...
0
votes
1answer
458 views

Find nearest values from MySQL Table

I want to fetch nearest rates for a given value from below table. mysql> select * from rates; +------+----------+----------+ | ID | Type | Rate | +------+---------------------+ | 1 | ...
0
votes
1answer
729 views

How to get performance benefits from a view vs subquery?

I'd like to know how/if anyone has gained significant performance benefits from using views instead of subqueries. I would prefer not to define a specific case, since I'm trying to establish good ...
1
vote
1answer
2k views

Mysql: update query with subquery

Hello i need to perform the following query Query update Taxonomy set sourceId = ( select id from TaxonomyMapping a where a.oldId = ( select cm.en_ID from TaxonomyMapping ta ...
0
votes
1answer
217 views

Trigger - Add to a date using a subquery

(postgresql 9.2) I'v 2 tables Table 1 (extinguisher) extinguisher_id (serial) type_designation_extinguisher_type(text) manufacturing_date (date) life_date(date) Table 2 (extinguisher_designation) ...
0
votes
1answer
118 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, ...
2
votes
1answer
822 views

Oracle 10g: Optimizing an update query that uses a subquery

I have the following query within a stored procedure, and I've been trying to improve its performance to no avail. UPDATE TBL_REPORTING REP SET (REP.ISSUER_ID, REP.ISSUER_NAME ) = ( ...
0
votes
1answer
337 views

How to update a table by count from another table?

I have two tables as CREATE TABLE country_statistics ( id int(11) NOT NULL AUTO_INCREMENT us int(11), uk int(11), ca int(11), PRIMARY KEY(id) ) ENGINE=InnoDB DEFAULT CREATE TABLE entries ( id ...
2
votes
1answer
1k views

SQL Server select with regex

Can we use regular expression to select the item from database? The table item is like below Table column|name| 10.01.02 | a | 100.2.03 | b | 1021.10.04 | c | Now my problem is that i ...
1
vote
2answers
395 views

Improve performance with the WHERE NOT IN sub-select clause

In the following query, I have to count transactions for each customer. [EDIT]However, I have to exclude from the result set entirely, customers that have a transaction older than one year. ...
1
vote
2answers
124 views

Using max for each sub group does not seem to work.

I have a table that looks like this in Oracle 11g: +----------------------------------------------------------+ | ACCT_NBR | MAIL_TY | ORGA | PERS | RUN_DATE | ...
2
votes
1answer
338 views

Subselect dependent on first select value

I wish to do a select of all data matching a particular id. I would also like to return a selection of all data matching the alt_id field in the first select. This example works fine for the main ...
1
vote
1answer
103 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 ...
0
votes
2answers
77 views

Query keeps on executing

I'm executing below query, but it keeps on executing. In place of some time I have a time value. select distinct(col1) from table1 where col2 > 'some time' and col1 not in (select ...
-1
votes
1answer
3k views

Delete from table where multiple fields match select subquery from other table

I want to delete an entry in a table where multiple fields match the results of another select subquery which takes data from another table. This is what I have so far, though it doesn't work: ...
2
votes
1answer
158 views

Filter on a window function without writing an outer SELECT statement

Since window functions cannot be included in the WHERE clause of the inner SELECT, is there another method that could be used to write this query without the outer SELECT statement? I'm using Oracle. ...
-4
votes
0answers
43 views

oracle database query [closed]

I have a problem in writing a Database Query Problem: I have the below fields in my table Fields: Primary_ID(PK) ,E_ID, Bank, REQUEST_STATUS, START_DATE, STATUS Data: REQUEST_STATUS may contains ...
0
votes
2answers
2k views

Use an Alias in Where Clause Subquery

I need to show some fields from another table in Oracle. Here is my query: SELECT ANGGARAN.SIMPEG_PEGAWAI.ID_PEGAWAI AS KODE, ANGGARAN.SIMPEG_PEGAWAI.NAMA, ANGGARAN.SIMPEG_PEGAWAI.NIP, ...
1
vote
3answers
2k views

How do I use subquery on the same table in MySQL?

I have a query like this which takes a really long time to run. The table is around 4 million rows. DELETE FROM TABLE WHERE value_was IS NULL OR value_was <= value_now; I'm hoping I could ...
0
votes
2answers
806 views

How to use and optimize subquery on 100 million rows

What I'm trying to do is running a job on more than 100 million domains which haven't processed before. I have two tables, "domain" and "domain_setting", on every batch (10.000 domains per batch) I'm ...
2
votes
1answer
846 views

Best practice: Unions or a derived table?

I've inherited a medium-sized database with a terrible schema. The sanitized portion in question is like so: CREATE TABLE `pending` ( ... `invoice` int(11) DEFAULT NULL, `lid` int(11) DEFAULT ...
0
votes
3answers
280 views

Not getting the expected result with 'IN' and subquery

I am trying to access the ring_to_number from tbl_destinations that holds all the numbers. And field destinations has the comma separated ID like 1,3. but according to this query i just get the the ...
1
vote
1answer
48 views

Identical subquery optimisation in an update

update activitybooking set `submitted`='1' where id='958' and (select SUM(pool1_count) from (select pool1_count from `activitybooking` where `abt`='12' and (id='958' or ...
1
vote
1answer
651 views

MySQL subqueries that use range based on values of main queries don't use indices properly

I think I've isolated a problem that has been affecting many of my queries lately. And would like some help to figure out a solution for this. Ok so my findings are that a normal query that runs very ...
2
votes
1answer
837 views

Selecting minimum value using a subquery

I need to write a query to grab the lowest price from each merchant and output the price link (p_link) and some other information such as merchant name + rating. We have a table for prices ...
2
votes
2answers
839 views

Why do I need to use a sub query to filter down a grouped select?

If I do this -- SELECT dv.Name ,MAX(hb.[DateEntered]) as DE FROM [Devices] as dv INNER JOIN [Heartbeats] as hb ON hb.DeviceID = dv.ID WHERE DE < '2013-03-04' GROUP BY dv.Name ...
1
vote
1answer
76 views

Why is this query so slow?

I have a quiz site with approx 2000 questions. The function in question worked great when I wasn't tracking that many users, but now there are 300,000 question that users have seen. The function only ...
7
votes
2answers
8k views

SELECTing multiple columns through a subquery

I am trying to SELECT 2 columns from the subquery in the following query, but unable to do so. Tried creating alias table, but still couldn't get them. SELECT DISTINCT petid, userid, (SELECT ...
0
votes
1answer
333 views

Delete with subquery with no unique columns

I have a table LIKES (ID1, ID2). Both id1 and id2 are non unique columns. Database is SQLite delete from LIKES where ID1 = 10 /// Wrong there more then one record with ID1=10 delete from LIKES ...
2
votes
1answer
999 views

Select multiple columns in subquery

I am having trouble selecting all cloumns in a sub query and can't seem to get no where with joining for replacement. http://sqlfiddle.com/#!2/2481e/1 The link is to the schema with my current ...
4
votes
1answer
69 views

does a subquery pull the entire table?

i am attempting to run a subquery in a table: SELECT t1.*, t2.* FROM t1 LEFT JOIN (SELECT * FROM table2 GROUP BY col1) AS t2 on t1.col1 = t2.col1 WHERE ... My main question is, since that subquery ...
0
votes
0answers
41 views

Consolidate does not work with my subquery [duplicate]

Possible Duplicate: SQL Subquery , One to Multiple rows Following query I have written returns the result as expected, example 121350 rows. SELECT ...
1
vote
1answer
816 views

Postgresql nested row_to_json not working

This probably wouldn't be an issue if I were using postgresql 9.2, however I can't (yet) upgrade from 9.1, and I'm using the json data type extension for 9.1. I'm trying to achieve a json object like ...
2
votes
1answer
261 views

Does MySQL have problems with nested insert like with subqueries in where?

Query 1: INSERT `personal`.`locations` SELECT DISTINCT `s`.* FROM `references` `t` JOIN `locations` `s` ON `first_id` = `s`.`id` WHERE `lat` >= 37.3 AND `lat` <= ...
2
votes
3answers
2k views

SQL Subquery , One to Multiple rows

Following query I have written returns the result as expected, example 121350 rows. SELECT dbo.Articles_in_Consignment.Consignment_id, dbo.ORDER_D.Orders_boxsize, ...
3
votes
1answer
3k views

Subqueries run very fast individually, but when joined are very slow

ypercube solved the problem. Subqueries were totally unnecessary, and the whole thing works with plain joins. It is still strange that MySQL's optimizer could not make use of my original query, ...
0
votes
2answers
309 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 , ...
2
votes
2answers
157 views

Query taking too much time

My query is taking too much time to execute. Please help me here. mysql> explain select pcm.catalog_id from cat_produ_catal_map_defer pcm, cat_catal_catal_map_defer ccm, cat_catal_defer c ...
1
vote
1answer
280 views

How to re-arrange rows to best fit within groups?

I categorized a table with the method introduced here to categorize my items to folders with a limit size of 100. mixing_order id num_items cat order_in_cat cumulative_sum folder 1 ...
3
votes
1answer
256 views

How Can the Same Query in Two Nearly Identical Instances Generate Two Different Execution Plans?

Server A and Server B have identical hardware and instance configurations (A is Production, B is QA). B's DBs were restored from A's backups from one week ago. I was provided this query by the ...
-3
votes
2answers
758 views

Optimisation sub query SQL Server

I would like to optimise the query below because it's actually taking 40% of the time in the real one. I HAVE to get the first line in the table 2 for each line in the table 1. The relationship is 1 ...
2
votes
1answer
403 views

How to speed up a query with a lot of subqueries

I have a query which uses a series of functions to return the status of each document for a loan. SELECT loan_number, borrower_name, get_application_status(loan_number, ...