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Questions tagged [union]

Combines two or more query results. UNION removes duplicates; UNION ALL retains all rows.

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90 views

Microsoft SQL Server 2014 Nested From Query in Cross-Apply

When selecting from a nested query in an OUTER APPLY statement the nested query seems to be evaluated only once in certain circumstances. Bug reported to Azure Feedback Forum: https://feedback.azure....
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2answers
40 views

Alternative to slow [LEFT JOIN + OR] without UNION?

I have a reasonably simple query that returns all purchases for a given user, searching by his government issued id. The document could be in two different tables. The query using only left joins ...
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27 views

Union the same table. Optimize query

I'm coming with a question about merging two data sets. I am using STI (single table inheritance) in the products table, so one column defines what type of product the specific row stores. The ...
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1answer
44 views

Union from Multiple Tables in many databases and group results in batches of n

First post in dba, so please be gentle. I have a project I am working through and have 4+ SQL Server databases to work with. These DBs contain 2 (or more tables) I wish to UNION the results from. ...
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1answer
29 views

SQL db query using UNION and Left Join

I have 6 tables (t1, t2, t3, ...,t6 in the same SQL Server 2008 R2 database. I wanted to group them into two. Group 1 (TG1) includes tables 1, 2 and 3. Group 1 (TG1) includes tables 4, 5 and six. I ...
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12 views

I'm trying to order a table with 3 columns as if the columns were merged into 1 such that it would sort as 3 separate entries

I've hit a somewhat unique obstacle with my current project. Below is a mock MySQL table to better describe the issue I'm trying to solve. mysql> describe `minimized_event_instructions`; +---------...
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0answers
17 views

How to fetch different record when nothing matches in where conditions in the same query?

I am using ORACLE 12C database. There are two components - Agreement and Case. Agreement related information stores on Agreement_line and Object Table. Common column between these tables are ...
0
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1answer
47 views

Is it faster to split a large table into 12 rolling monthly tables & use UNION them for reports or keep large table & delete rows older than 1 year?

My co-worker wants to split a large 158M row stats table into stats_jan, stats_feb, ... and use UNION to select from them for reports. Is that standard practice and is it faster than to just use the ...
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2answers
82 views

How to sort rows after union

I have two tables that I want to combine. I need to be able to show all DelDates that had changes from the original (record 1). Record 1 as the first Record and Record 0 (table 2) always being the ...
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1answer
1k views

Msg 8114, Level 16, State 5, Line 1 Error converting data type nvarchar to float

I created some select statements which run without any problem in SQL Server. Then I joined them together with UNION and got this error message> Msg 8114, Level 16, State 5, Line 1 Error ...
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0answers
40 views

Does MySQL Lazy Union really work?

Following query is an example of Lazy Union: SELECT GREATEST(@found := -1, userId) AS userId FROM user WHERE userId = 1 UNION ALL SELECT userId FROM user WHERE userNumber = 1 AND @found IS NULL UNION ...
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1answer
1k views

syntax error at or near “AS” [closed]

I have a program that takes in one or more than one table names, from a list stored in a reference table and runs a SELECT query on it. so I retrieve the table names and insert it into the SELECT ...
3
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2answers
28 views

Optimizing PostgreSQL where clause with OR

I have a query that uses an or in the where clause. It is slow. It seems that re-writing the query using a union could get the same results much quicker. But I'm in an environment where we generate ...
1
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1answer
26 views

Get the combined row count by month from 3 tables

Using Postgres 10+, I have three tables with similar structures, where I'm trying to get a count of rows grouped by months. I have a functional query working for two tables, as below: CREATE TABLE ...
0
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1answer
206 views

Will too many tables slow Mysql down?

I'm making a database which should be able to handle over 1,000,000,000 rows. in order to optimize it's performance i've decided to split tables. so instead of having 1,000,000,000 entries in one ...
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1answer
59 views

Print Two Different Columns with Union All- SQL

I have an SQL statement like this, SELECT * FROM (select "John" as FirstName Union All select "Mary" Union All select "Alis"), (select "Doe" as LastName union all select "Queen" union all ...
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0answers
20 views

Combine multiple queries that each require a row of input values

I'm looking for a way to combine multiple queries that each need two values. For example, I can look up a patient's age and weight as follows: select age , weight from patients join ...
0
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1answer
162 views

Oracle DB union two select statements which return multiple rows

I am trying to create a union inside a stored procedure which unions two select statements. One of the select statement returns two or more rows. Thus I get the error "exact fetch returns more than ...
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1answer
46 views

Handle 4 tables and to show 4 columns as result

i can't figure out how to build the correct query that involves 4 tables and shows these 4 columns: I want to show this 4 rows, each from a different table. EDIT: Each company belongs to a Sector. ...
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2answers
83 views

MySQL Select Union; Filter by Shared Relation?

Currently, I have 3 tables (see structure below), speakers, venues, and events. I'm trying to do a relevance search on the names of the speakers and venues. However, on the Search Results page, if the ...
0
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2answers
39 views

MYSQL search for each name in 2 columns and add values associated for each player

I have a database "game_results". It contains the following: PlayerID (int not null primary key auto increment) player1 (varchar) p1destroyed (int) player2 (varchar) p2destroyed (int) winner (...
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1answer
359 views

Backend Table/Row Locking Structure using CTE Queries

This question is an extension of a previous question that I asked. Table Locking When using Unions With the same query we are using that is causing blocking the various queries used in these UNIONS ...
2
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1answer
323 views

Table Locking When using Unions

When multiple selects are used in a UNION/UNION ALL are the table locks for each individual SELECT statement handled individually or are all table locks held until all SELECT statements are completed? ...
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2answers
47 views

Remove multiple joins to same table with where

I am stucked at below situation. Need expert advice. I have 3 tables, login_details,deleted_login_details and custom_fields as below. login_details structure = deleted_login_details custom-fields have ...
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1answer
137 views

Oracle Subselect Union Multiple Column

I want to select and count all cats and dogs at one location; location | cats | dogs | new york | 150 | 66 | paris | 34 | 12 | What I've got so far: SELECT cats,dogs FROM (select ...
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1answer
29 views

MySQL, comparison between, tables with not all records common, on 2 time intervals

I want to make comparisons on the volume of sales, turnover and margin of all product sales between 2 time intervals (2017-10-1 to 2017-10-31 ) and (2018-10-1 to 2018-10-31). for example: Product ...
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0answers
61 views

Count neighbors and sum of the neighbors values

I am looking at an edge and adjacent edges. Edge priority decreases with (1) Decrease of edge weight (2) Increase of the number of neighboring edges (3) Increase in total weight of shortest distinct ...
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1answer
48 views

Selective union possible?

Is there any way to make a UNION consider only specific columns when checking for duplicity? The query below returns all of the columns that I need but, due to slight differences in some of the ...
0
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1answer
303 views

join two tables, include one row from the parent table for each primary key

I've got a simple join over a primary and foreign key... but I need to include a row from the parent table in the results for each primary key as a sort of header row for the children. For instance, I ...
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1answer
105 views

Simplifying the “repetitive” code of a query involving UNION ALL, WHERE and LIMIT

How can I simplify the code of the query shown below? Requirements are always the same as I describe as follows: (select * from questions where points = 3 and type = 1 order by rand() asc limit 6) ...
0
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1answer
3k views

Execute UNION and after LEFT JOIN in MySQL

I have 3 tables cdc_vw_Marbetes_Catalogo_Exis tblMarbetesAdicionales tblMarbetesCongeladas First I make a UNION of the tables cdc_vw_Marbetes_Catalogo_Exis with tblMarbetesAdicionales. (SELECT ...
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1answer
14 views

union only dispalying the first query

First time posting in Stack Exchange so excuse any faux pas (well let me know them of course). I'm using union for the first time on an already Frankenstein'ed query I've pull together so I'm looking ...
3
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1answer
430 views

Query with conditional JOIN running slow

I have a query the first part of which looks like this - With CTE AS ( select DISTINCT A.col1, A.col2, . . . from tableA A JOIN tableB B ON ( ...
2
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1answer
543 views

Optimze performance for LIMIT / OFFEST on collected result of multiple queries

I have large tables in Postgres 10.4 (many millions rows) and three piped SELECT queries. The percentage of rows contributed to the total result for each SELECT is roughly: SELECT 1 : ~5 % rows ...
3
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1answer
2k views

Fastest MySQL pagination and ORDER from a huge UNION ALL VIEW

Let's say we have a schema with table 'month' which have the current information and table 'year' which have the historic information. Each table has around 65,000 rows. This schema exists in several ...
0
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2answers
120 views

What is the F301: the CORRESPONDING clause in query expression?

The SQL 2011 Spec supports a CORRESPONDING clause, Feature F301, “CORRESPONDING in query expressions”: What is this feature? How is it used? And, is it supported by any industry RDBMs?
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1answer
28 views

MySQL - Query Main Table Rows and All Children from it's rows on the same query

I have the view_product which contains what i need and i have many child tables for it. Currently i have a query where i get everything in a single query (unions) and programmatically split and ...
0
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1answer
77 views

SQL Query: Column Name as Value

I have a Redshift table that looks like the following: +----------------+---------------+------+ | FieldA | field1 |field2| +----------------+---------------+------+ | ABC | ...
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1answer
500 views

Joining two tables with unrelated where clauses

I have two tables: (EMPAssignments) and (EMPloyees). Both have an employee id column. EMPAssignments has columns for employeeid, assignment, and ftepercentage: employeeid assignment ftepercentage ...
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1answer
71 views

How to make this query simpler

SELECT IH.InvoiceNo, C.Name AS NameofCustomer, IP.Amount AS CashAmount, 0 CreditNote, 0 ChequeAmount, 0 Credit, IP.Amount AS SalesValue FROM InvoiceHeader IH LEFT JOIN ...
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0answers
211 views

Another form of WHERE NOT EXIST

I have two complex queries and I have to filter out the results from the second one, it looks something like this: SELECT STH INTO #temp_table_1 FROM TABLE1, TABLE2, TABLE3 WHERE TABLE1.ID = TABLE2....
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1answer
920 views

SQL Query For Displaying 'No Data Found' for values containing null and 0 along with other records

The following was one of the practice questions in the online course i took on udemy for SQL. I have a table 'emp' and consider the below names in the query map to their corresponding columns in ...
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1answer
30 views

Output of UNION query [closed]

UNION Suppose 2 SELECT queries are joined by UNION. Can I get output if the 2nd SELECT query has 0 rows and 1st SELECT query returned some rows?
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2answers
517 views

merge 3 mysql tables into one with no duplicates

I would like to merge 3 tables data, each have a number column in common, but all the other data differs. What I would like to achieve is selecting all of the data from the common column and merging ...
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4answers
1k views

Check if two tables have the same structure (are compatible)

I was wondering if there is an established way to test if two PostgreSQL tables/relations have the same structure. In other words, how to test whether they are compatible with each other in the sense ...
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2answers
1k views

Problem with union casting integer to ceiling(decimal)

I have this scenario, it looks like MySQL is taking the largest decimal value and tries to cast the other values to that. The problem is that this query is generated by an external library, so I don'...
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1answer
1k views

Merge data with UNION ALL and INNER JOIN in MySQL

I try merge a data to one row. I have query: (select t.`id`, t.`coins_id`, t.`first_coin`, t.`second_coin`, t.`price` as `price_old`, null as `price_young`...
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2answers
4k views

Select all columns with same name from different tables

I have 4 tables. In 3 of these, there are a column named ACTIVE_FL which can have a value of "Y" or "N". How can I select, from all tables only the columns ACTIVE_FL which have as value "N" ? I ...
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2answers
35 views

unmanaged data in union

Forgive me if this question already ask,not much of db guy here , here is what i tried, select row_number() over (partition by name order by challanto_date) , * from ( select rma, ...
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2answers
182 views

Select multiple rows with different criteria for each [closed]

I am trying to put together a query will return sales information across multiple date ranges. I was planning to do something like this: SELECT count(*) AS thirty_day_sales FROM "MySchema"."MyTable" ...