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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649 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 ...
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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 ...
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1answer
204 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) ...
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1answer
105 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, ...
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1answer
689 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 ) = ( ...
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1answer
317 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
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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 ...
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2answers
374 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. ...
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2answers
121 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
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1answer
307 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 ...
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1answer
102 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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2answers
76 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 ...
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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
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1answer
148 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. ...
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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 ...
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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, ...
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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 ...
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2answers
765 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
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1answer
771 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 ...
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3answers
253 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
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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
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1answer
610 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
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1answer
765 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 ...
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2answers
776 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 ...
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1answer
75 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 ...
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2answers
7k 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 ...
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1answer
308 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
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1answer
979 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
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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 ...
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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
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1answer
769 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
255 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
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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
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2answers
302 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
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2answers
153 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 ...
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1answer
273 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
241 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 ...
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2answers
714 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
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1answer
388 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, ...
2
votes
3answers
2k views

How do i subtract a number of days from a prepared statement parameter in db2?

I have a C# application using OLEDB to connect to a DB2 database. Basically, I want to do this: SELECT CALC.WEEK, COUNT(CALC.ID) AS TRANSACTIONS , SUM(CALC.SUBTOTAL) AS REVENUE FROM ( ...
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1answer
347 views

Getting max values from MySQL tables

I have three tables: competitions (id, name, date) athletes (id,name) results (place, id_athlete, id_competition, ranking_points) where: results.id_athlet=athlet.id ...
1
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1answer
193 views

GROUP_CONCAT with ORDER BY , but results are not ordered

The following query works fine SELECT *, (SELECT GROUP_CONCAT(url SEPARATOR '$$' ) FROM project_photos WHERE project_id = projects.id ORDER BY priority) AS images FROM projects WHERE catID = 2 LIMIT ...
0
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2answers
129 views

Are these two queries technically equal to each other?

Ran it in my query browser. I was am getting same results for both. But still need a confirmation. SELECT cs.RSCode , CustomerName , em.EmailId FROM Customer_STN cs JOIN ...
1
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1answer
51 views

Query from database

I have a table named mip. The table has primary key id, a foreign key product_id and a column usage_type. product_id is a primary key id to a table named product. It is one to many relationship from ...
3
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1answer
3k views

SELECT LIMIT 1 per column value?

Lets say I have the following table ----------------------------- | user_id | comment | ----------------------------- | 2 | thats cool | | 2 | awesome | | 3 | ...
3
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1answer
5k views

MySQL: Optimize UNION with “ORDER BY” in inner queries

I just set up a logging system which consists of multiple tables with the same layout. There is one table for each data source. For the log viewer, I want to UNION all the log tables, filter them ...
3
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2answers
248 views

Do MySQL sub-queries essentially use as much overhead as separate queries?

If I have a query like this: SELECT name FROM ( SELECT * FROM `table` WHERE id IN (1,40,300) ORDER BY AnotherColumn ) From a bandwidth and overhead standpoint, is that the same thing as doing ...
5
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1answer
832 views

Mysql sub query returns more than 1 row

SELECT * FROM wp_posts WHERE ID IN ( (SELECT courses FROM wp_category WHERE CatID =401) OR (SELECT meta_value FROM wp_postmeta WHERE post_id IN (SELECT courses FROM wp_category WHERE CatID =401) ...
3
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2answers
3k views

How to GROUP_CONCAT DISTINCT values in a MySQL query that gets number of records and min/max values?

I'm running MySQL 5.0.88 (Coldfusion8) I have a product search which I'm querying number-of-results as well as min/max prices/rebates across the product table. I also want to include a string of ...