The set of all distinct rows from two or more result sets.
2
votes
2answers
29 views
Postgres 9.2 select multiple specific rows in one query
I have a table with three columns,
Id Serial.
Value real.
timein Timestamp.
I want to select the values based on a range of days ie. from two days ago until now. The table may contain one or two ...
2
votes
1answer
68 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 ...
2
votes
1answer
42 views
Optimize UNION query in MYSQL
I have a problem with a UNION query in MySQL. We have 10 millions players on our website and we would like to select players with a multi-criterias system. For exemple, selecting US people, men, > 35 ...
0
votes
1answer
67 views
Mysql: order by field or select union?
As a newbie, I expected Mysql to return the rows of this query ordered by their ids order in the id clause
select * from test where id in (3,1,2)
Unfortunatelly for me, that's not true. The results ...
1
vote
1answer
39 views
Merge multiple “is exists” queries into one statement
I'm trying to figure out how to check if multiple rows exist in multiple tables in one statement.
Given the following tables:
table table_one
========
id
'a'
'b'
'c'
table table_two
========
...
3
votes
1answer
111 views
Unable to run union in parallel on SQL Server
I am unable to get this fairly simple query to parallelize the union operation:
select va.ObjectId, 0 as IsFlag
from Oav.ValueArray va
where va.PropertyId = @pPropertyId
...
0
votes
0answers
64 views
How can I get multiple rows instead of columns after self-joins?
This is my situation (the real table isn't about people but about paths):
[Table: People]
id | name | type | related_to
----------------------------
1 | | | 0
2 | Nico | Friend | ...
1
vote
2answers
47 views
How to Perform Two Simple Queries using Select Value from First Query
I need to perform a select operation and get the id column's value (single value returned). Using this value, I need to perform two more selects on the same table using UNION ALL (in order to select ...
2
votes
2answers
185 views
How can I do a differential query (delta plus/minus) telling me what rows are in view A that are not in view B and vice versa?
I have two views which use radically different means to accomplish what I hope is the same end view. One uses complex query expressions and walks entire giant tables and is highly expensive, and the ...
2
votes
2answers
471 views
Why won't SQL Server optimize the UNIONs?
Consider these queries (SQL Fiddle):
Query 1:
SELECT * INTO #TMP1 FROM Foo
UNION
SELECT * FROM Boo
UNION
SELECT * FROM Koo;
Query 2:
SELECT * INTO #TMP2 FROM Foo
UNION
SELECT * FROM Boo
UNION ALL
...
1
vote
1answer
160 views
MySql: #1221 - Incorrect usage of UNION and ORDER BY
I have the following query which is intended to retrieve the newest 3 comments for each post in an array of posts.
SELECT * FROM comment AS tbl WHERE sscm_id IN
(
SELECT sscm_id FROM comment AS t1 ...
3
votes
1answer
2k 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 ...
4
votes
2answers
368 views
Query two SQL Server databases in same function but on two different servers
Suppose I have two database servers (DB-SERVER-1 & DB-SERVER-2), and there is a single database on each server (DB1 & DB2). Both are SQL Server databases. Is it possible to query both ...
1
vote
1answer
537 views
How do I perform a UNION query on a dynamic list of tables?
My database has an unknown amount of tables, named with the same prefix followed by a random string: _ct_<random_string>.
Each of these tables has the same data structure.
I also have another ...
1
vote
1answer
126 views
What is a good way to query data stored in multiple identical tables split by date/time
I have a 3rd party piece of software which records data samples from industrial equipment. This data logging software stores data in sample data tables with approximately one day's worth of samples ...
3
votes
1answer
208 views
How can I conditionally summarize multiple rows in Microsoft Access?
I have a table of data, in Microsoft Access 2003, listing multiple rows for each person.
I want to conditionally summarize a subset of these rows for each person, for instance, if entry for columnA = ...
2
votes
2answers
394 views
Is there any way to speed up a query with 3x UNION on the same large table?
Assuming that the following query is legitimate and executes successfully, is there any way to speed it up?
SELECT foo from T1 --T1 is a huge (>5e6 rows) table with no indexes
UNION
SELECT bar ...
2
votes
1answer
971 views
Dealing with NULL values and EMPTY strings in UNION of two tables
I want return records from two database tables when a record differs in at least one of the fields.
I have written a query for it using the UNION operator. It is working absolutely fine.
However, I ...
1
vote
2answers
1k views
MySQL - INSERT INTO … SELECT … UNION
I'm having an issue with a fairly complex query where I need to store the ids from one table (based on heavy criteria) into a narrow, alternate table for future reference, but I keep running into a ...
2
votes
2answers
167 views
MySQL : UNION script help
I have two tables which have roughly the same data but we could not mix them together due to the nature of the data input and presentation and to keep the table size small.
We run the followign ...
1
vote
1answer
731 views
MySQL - SELECT INTO OUTFILE, with a UNION
Is it possible to issue multiple select queries whose resultsets are combined via union, into the same outfile?
What I am trying to do, but not working:
(SELECT email FROM table WHERE createdate ...
5
votes
1answer
1k views
How to make a union view execute more efficiently?
I have a large table (tens to hundreds of millions of records) that we have split for performance reasons into active and archive tables, using a direct field mapping, and running an archive process ...
2
votes
2answers
277 views
Union of Columns
I have some SQL queries that retrun the following.
Total Pre Orders Web
Total Pre Orders Phone
Total Orders Web
Total Orders phone
Each one of those queries retrurns a the query name and the count ...
2
votes
2answers
3k views
How to combine UNION and INNER JOIN?
I'm fetching the grandparent of all nodes in a tree as follows:
SELECT P.id, P.parent, GP.parent gp_id FROM product_groups P
INNER JOIN product_groups GP ON P.parent = GP.id
There is ...
5
votes
2answers
698 views
Perform UNION ALL regardless of column order in the two joined tables
SELECT * INTO TABLE1
FROM Table2
UNION ALL
SELECT * FROM Table3;
GO
I am using this query to stack two tables together into one table. These tables should have the columns in the exact same order ...
