All Questions
Tagged with sql sql-execution-plan
535
questions
0
votes
1
answer
810
views
NOT Equal(<>) in Oracle SQL is ignoring Index and NULL valued rows
I have one query where need to filter based on NOT Equal values in Oracle SQL. Can not use EQUAL to condition as the possible values fo the column in unknown.
Query:
SELECT * from employee where name &...
3
votes
2
answers
512
views
How do I get a PostgreSQL execution plan with parameters?
My application has a myriad of queries and I wanted to get the execution plan of some of them. Most if not
all of the queries have multiple parameters and I can't find how to get the execution plan ...
- 936
0
votes
1
answer
75
views
How to understand expain analyze output for query?
I have this query in my database:
INSERT INTO value2s(organization,
location,
device,
measurement,
timestamp,
interval,
average,
...
- 33k
1
vote
1
answer
106
views
Why does Oracle execute both TABLE SCAN and INDEX UNIQUE SCAN on the same table in one query?
I am not looking for a optimization of the following, just an explanation. I have this query:
SELECT COUNT(LARGE_A.id_a), SUM(LARGE_A.b_integer)
FROM LARGE_A
INNER JOIN MEDIUM_A ON LARGE_A.id_a = ...
- 2,011
1
vote
1
answer
78
views
Similar Query different execution plan and performance
This is the script I use to generate 10M rows on Clients table from 200 different cities. (It took 11 minutes on a desktop PC)
*Important note at the end
-- Crear la tabla Clientes
CREATE TABLE ...
- 126
1
vote
1
answer
83
views
Why does the location of the SUM() in an IF statement matter in a GROUP BY scenario when the grouped by column is changed? (BigQuery)?
I have some electrical meter data that I want to group by meter and convert all data to baseline units. The below query does that:
SELECT meter,
IF(unit="kWh" OR unit="kW", &...
- 109
1
vote
1
answer
303
views
SQL Server hash match when joining to view
I have a subquery, which always return 1500 rows, because of TOP 1500 on the beginning. It gets left joined to a view, which returns 15mil rows if called outside any context. And in execution plan I'm ...
- 359
6
votes
1
answer
424
views
How to see the execution plan of a multi-statement table valued function in SQL Server?
I have a view in SQL Server that calls a function. When I show the actual execution plan for querying the view, what happens inside the function is completely opaque though.
As a small example, I made ...
- 3,653
0
votes
3
answers
372
views
How to improve slow query performance?
I have a multi-join query that targeting the hospital's chart database.
this takes 5~10 seconds or more.
This is the visual expain using mysql workbench.
The query is below.
select sc.CLIENT_ID as '...
- 163
0
votes
0
answers
56
views
Almost equal table with different running time
I’m using oracle. I have two table A and B
Table A has 8000 rows and 5 five columns
Table B has 5500 rows and same 5 columns
All of 5500 rows in table B are contained in Table A and they are the same
...
- 1
0
votes
1
answer
187
views
How to prevent SQL Server from running the same subquery multiple times
I have a query that follows the following structure:
SELECT *
FROM
... <generated code> ...
(SELECT <fields>,
CASE(SELECT TOP 1 ID FROM [Configuration] WHERE IsDefault=...
- 2,647
0
votes
0
answers
67
views
SQL INNER JOIN vs WHERE IN big performance difference
I have read multiple sources and still don't understand where a big difference comes from in a query I have for Microsoft SQL Server.
I need to count different alerts linked to vehicles (IdMateriel is ...
- 73
0
votes
1
answer
130
views
SQL Server 2022 : unique index with two columns not working correctly
I have a table with users with over 50000000 entries. I want to check for the presence of already registered users on the server and I execute this request.
SELECT *
FROM
(SELECT TOP (1000) *
...
0
votes
2
answers
372
views
How to fine tune SQL Server query execution plan generation?
I have a large "Deals" table (1.3 million rows) that needs to be displayed on a paginated grid in my application, the application also includes filters to help the user search through those ...
- 2,647
0
votes
0
answers
68
views
Why doesn't computed column calculation show up in the the Execution Plan?
I have a table with a computed column. It is not persisted.
create table dbo.Cases (
...
CaseName varchar(20) not null,
NickName AS (dbo.fn_ParseCaseNickName(CaseName)),
...
)
When I execute ...
- 61.1k