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.

learn more… | top users | synonyms

1
vote
1answer
13 views

Determine existence in recursive working table

I have a query that needs to check for existence of each input row type in another table, but it is unnecessary and inefficient to check for existence of subsequent rows of the same row type if one is ...
0
votes
0answers
26 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
1answer
61 views

How to make a single row result query to return multiple rows

I have the following WITH SQL Query which does select a set of filling stations along a route within the distance of 1000m. To have the measurement in meter I cast the geometries to geography. I also ...
2
votes
1answer
117 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 ...
2
votes
1answer
2k 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 ) = ( ...
1
vote
1answer
53 views

Is it possible to emulate the WITH command in MySQL 5.1.73? [closed]

I have the following query: SELECT COUNT(*) AS `count` FROM agreements WHERE start_date >= STR_TO_DATE('14-01-2015','%d-%m-%Y') AND start_date < ...
0
votes
2answers
110 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 ...
0
votes
1answer
41 views

problem with query two different tables with foreign key relations

I am having a problem with querying two tables with different foreign key relations... My first query works fine but when adding another table with a different set of relations I am having a ...
1
vote
1answer
96 views

Postgres error [column must appear in the GROUP BY clause or be used in an aggregate function] when sub query is used

I have two tables employee and phones. An employee can have 0 to n phone numbers. I want to list the employee names with their phone numbers. I am using the below query which runs fine. SELECT ...
1
vote
2answers
47 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) ...
0
votes
1answer
127 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
121 views

MYSQL query to find records between two date range

I am working in a web application using PHP and MySQL. I have two tables Employee employee_id email_id 3 tl1@jasmine.com 4 agent1@jasmine.com 5 ...
1
vote
1answer
3k views

MySQL Subquery returns more than one row

I have a table namely tbl_plays. It has the following columns and data id(PK)| gameid | drawid | etc ---------------------------------------------- 1 | 1509 | 73 | ...
0
votes
0answers
23 views

Sub queries in Apache Hive

I have a table with following structure col1 col2 col3 col4 category 300 200 100 20 1 200 100 30 300 2 400 100 100 70 1 100 30 200 100 ...
0
votes
1answer
69 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
160 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, ...
3
votes
2answers
84 views

Why wouldnt Mysql use index on the Primary query in a nested query

I have two tables: search_criteria and pricing. There is an index on search_id column in search_criteria table and on pricing_id column in pricing table. But running this nested query does not use ...
1
vote
2answers
1k 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
31 views

Email open rate calculations in subqueries with postgres

So I'm relatively new to PostgreSQL, but here we go: I have a pgsql database that is receiving HTTP Post Email Events from my Sendgrid email server, and am trying to make a dashboard that displays ...
1
vote
1answer
90 views

MySQL: Why queries with subqueries are much faster than single query?

I made few queries on my db lately First query: SELECT `table`.* FROM (`table`) WHERE table.id in(27172172,[...bunch of ids...],27171770) ORDER BY field (`table`.`id`, ...
1
vote
1answer
32 views

Slow execution of a subquery with 0 matches

In MySQL, I have two basic tables - Posts and Followers: CREATE TABLE Posts ( id int(11) NOT NULL AUTO_INCREMENT, posted int(11) NOT NULL, body varchar(512) NOT NULL, authorId int(11) NOT ...
0
votes
2answers
65 views

Solution on a complex sub select query SQL Server

I created a SQL query that requires me to pull data from 2 separate databases, and I noticed that what I did is this: Select *, (Select Z.f From DatabaseZ.TblZ Z where Z.w = A.w) as valueZA, ...
0
votes
1answer
38 views

Select products and include all cities it belong to

I have 2 tables : PRODUCTS +----------+----------+----------+----------+ | id | title | content | city | +----------+----------+----------+----------+ CITIES +----------+----------+ | ...
0
votes
1answer
33 views

How to model efficient permission checks for a social network?

The goal is to build a facebook like permission system. So that users can grant other users access on objects based on a direct assignment (allow user X to see posts) or allow users to access them ...
0
votes
1answer
91 views

Identify faulty sub-query (subquery returned more than 1 value)

I am trying to resolve an issue with a query that fails with this error: Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when ...
0
votes
4answers
101 views

Why does this query take 32 sec to execute?

I keep my history records in one table and my pertinent data in another. I want to grab only the files from myfiles that currently have a given status recorded in statuses (ie, the latest status is ...
0
votes
1answer
31 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
2answers
77 views

Update specific records of table based on subquery's output (sql server)

have this query which produce below output : select sec.site,sec.Name,sec.Freq from ( select Name from sec group by name having count(Freq) > 3)as dt inner join sec on dt.Name = sec.Name where ...
2
votes
1answer
1k views

Select multiple columns in subquery

I am having trouble selecting all columns in a sub query and can't seem to get anywhere with joining for replacement. My Table Data is: CREATE TABLE `w7nwd_com_mtapp_product_engine` ( `id` ...
1
vote
1answer
74 views

Oracle: summing column value with subquery?

Are there some restrictions in Oracle that disallows to have a WHERE clause that compares value of column+(subquery count(*))? If the subquery table is empty, count(*) doesn't yield to zero in this ...
0
votes
2answers
55 views

Subquery or multiple left joins, or both?

I have two tables, for simplicity table1, with id as Primary key, and a field name, and table2 with the same. Each table has quite a few records, but during a complicated form process, the user is ...
0
votes
2answers
45 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?
0
votes
1answer
129 views

Alternative to sub query in MS Access

I'm looking into the possibilities for writing queries in MS Access, as my client currently uses Access and would be reluctant to move away to SQL Server. I've been using the data macros (which are ...
1
vote
1answer
1k views

CROSS APPLY versus INNER JOIN

I was reading a lot about CROSS APPLY versus INNER JOIN recently. I tried writing some queries and they both work in a similar fashion, the execution plan seems to be same as well. Maybe someone ...
0
votes
2answers
50 views

How are derived table implemented in MySQL

When MySQL makes a derived table as a result of SELECT (SELECT ...) etc or SELECT * FROM a JOIN (SELECT * from B) etc or SELECT * FROM (SELECT ...) Are these derived temporary tables created ...
0
votes
2answers
57 views

How to rewrite subquery to return only 1 row

I need to somehow check if query result is NULL, MySQL returns error Subquery returns more than 1 row. How should I rewrite it in order to work correctly please? SELECT DISTINCT user.id, ...
0
votes
1answer
56 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
186 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
47 views

SQLITE table joining with group

MESSAGE TABLE USERS msg_id | msg_to | msg_from | msg_body | msg_date user_id | user_name 1 1 2 hi 22/1/14 ...
0
votes
2answers
30 views

calculating max and joining tables

Just need a little help as new to SQL. I have a table which contains readingtime (records every 4 seconds during the day) and an energy reading. I wanted to know how much energy was used in a day. ...
2
votes
2answers
232 views

“All joins can be rewritten to sub queries”, is this statement true?

I wonder if there any case that a join can not be converted to a sub-query. BTW: I am not discussing advantages and disadvantage of using sub-query or using join.
2
votes
2answers
51 views

Compare multiple field to single IN query

I have a situation where I need to compare 3 different fields of a same table to a single IN query, eg: select unit from trips where owner1,owner2,owner3 in (select id from login) Can this be done ...
-1
votes
1answer
78 views

View vs TableValued Function vs SubQuery

I have a scenario where i need to join with 3 tables to get the value for one field for second field join with 4 tables for third field join with 3 tables all above joins are inner and if data ...
1
vote
4answers
43 views

where clause: if this value from col x make sure col y is this value

I feel like this is an easy one for you Experts! I haven't done any kind of Advanced SQL in years. Fundamental question: select * from myTable where ((if col1 = 'this', make sure col2 = ...
0
votes
2answers
24 views

Is my subquery inneficient. It is extremely slow

I have two tables. Member information and login entries. I am simply trying to display the member information table sorted by the last login access date. So i created this query, but it is extremely ...
0
votes
1answer
28 views

Count(*) as rolecount, filter by rolecount = 1

How can i filter out the rows who only got rolecount = 1? WHERE rolecount = 1 gives an error. Can't really figure out how to do it. SELECT u.uid AS uid, u.name AS name, u.picture AS picture, ...
3
votes
1answer
4k 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
1answer
58 views

If a query contains two identical subqueries, will they both run?

Say I have a SELECT query that contains two identical subqueries, like the below: SELECT (SELECT SUM(Price) FROM Product p WHERE p.GroupID = g.GroupID) AS 'TotalCost', (SELECT SUM(Price) ...
1
vote
1answer
105 views

Selecting data from multiple rows and insert it into a column

My table is like this: temp1 name city phone_no pincode ----------------------------------- amit Delhi 12345 123 Rajiv Bombay 836536 432 How do I transform the last ...
0
votes
2answers
1k views

How to find the same salaries and department names?

Write a query to display last name ,department number,and salary of any employee whose department number and salary both match the department number and salary of any employee using the following ...