logo
down
shadow

Extreme query optimization with IN clause and subquery


Extreme query optimization with IN clause and subquery

By : Stephen Sides
Date : November 14 2020, 04:48 PM
around this issue I've found that MySQL tends to perform better with JOIN than correlated subqueries.
code :
SELECT ch1.*
FROM citizens_dynamic AS ch1
JOIN (SELECT id, MAX(update_id_to) AS update_id_to
      FROM citizens_dynamic
      WHERE id IN (4369943, ..., 4383420, 4383700)
      GROUP BY id) AS ch2
    ON ch1.id = ch2.id
WHERE ch1.id IN (4369943, ..., 4383420, 4383700)


Share : facebook icon twitter icon
Query optimization: max() in subquery

Query optimization: max() in subquery


By : Sh42
Date : March 29 2020, 07:55 AM
wish helps you MAX always process all rows - use order by and limit - so query will look this way
code :
 SELECT * FROM wbsites WHERE url = '...' ORDER BY id DESC LIMIT 1
Risk-Parity Portfolio Optimization using Extreme Optimization in C#

Risk-Parity Portfolio Optimization using Extreme Optimization in C#


By : SNIPJop_
Date : March 29 2020, 07:55 AM
it should still fix some issue If the objective function computation throws, I strongly recommend that you run the code through the debugger to identify the exact location of the throwing code. My first bet is that the error happens due to vector size mismatch, for example in the matrix-vector multiplication. If you get to the bottom of this error, chances are that the optimization will then run smoothly.
If you want to try alternative algorithms instead, you might want to take a look at one of the following solutions. They all support specification of (non-) linear constraints, and it is not necessary to provide objective function and constraint gradients.
Subquery in Linq query giving A query body must end with a select clause or a group clause

Subquery in Linq query giving A query body must end with a select clause or a group clause


By : hoppjo
Date : March 29 2020, 07:55 AM
will help you The closing round paranthesis ends the query which needs a select at the end.
Why don't you use method syntax? It is much better readable in this case. Also, a Select is optional with .Where and method syntax:
code :
  join d in TourDates on t.TourId equals d.TourId
  where d.Date == dt
  select new
  {
       t.TourId,
       d.TourDateId,
       booked = Bookings.Where(b => d.TourDateId == b.TourDateId)
                        .Sum(b => b.NumberBooked()) 
  };
[Oracle]Optimization a query contain a max subquery

[Oracle]Optimization a query contain a max subquery


By : Alain Parmentier
Date : March 29 2020, 07:55 AM
seems to work fine Use an analytical function (single table scan) rather than a correllated sub-query (two table scans):
code :
SELECT product,
       price,
       quantity_in_stock,
       location
FROM   (
  SELECT product,
         price,
         quantity_in_stock,
         location,
         MAX( CASE WHEN quantity_in_stock > 0 THEN price END ) OVER ( PARTITION BY product ) AS max_price_in_stock
  FROM   MyTable
)
WHERE price = max_price_in_stock;
mysql performance optimization for a subquery in select clause

mysql performance optimization for a subquery in select clause


By : Deividas Brasas
Date : March 29 2020, 07:55 AM
This might help you In almost all cases, MySQL punts when it encounters a "prefix index" (INDEX(..., coords(25)). Specifically, it cannot claim "Using index" since the index is not "covering". That is, it may need bytes after the first 25.
Since idx_providerIdCoords and idx_providerId are identical, you should not expect the Optimizer to use one instead of the other.
code :
PRIMARY KEY (`id`),
KEY `idx_providerId` (`companyId`,`coords`(25)),
KEY `idx_providerIdCoords` (`companyId`,`coords`(25))
PRIMARY KEY(`companyId`,`coords`),
KEY (`id`)
Related Posts Related Posts :
  • MySQL join optimization - bypassing filesort
  • How to Select record with the maximum value in a GROUP BY?
  • MySQL Innodb Full text Proximity Search Gives Horrible Performance
  • MySQL best approach for db normalising, relationships and foreign keys
  • How to update one table based on the count value of another table while matching ids?
  • MAMP Pro 5.1.1-terminates MySQL when quitting
  • SQL - Get date of most votes cast
  • "Fuzzier" search in mysql
  • Tracing mysqld Using SystemTap
  • SELECT + INSERT + Query Cache = MySQL lock up
  • SQL vs. NoSQL for medium complexity search systems
  • SQL Error when creating table
  • Is it possible to write a query to compare rows to other rows in same table?
  • Display all duplicate records based multiple columns
  • summing time column in mysql
  • InnoDB: Cannot open table
  • Why is IN() considered O(logN) operation?
  • Can a deadlock occur on commit?
  • Is there a fast way to do a '%phrase%' search in any DB?
  • Is using an IN over a huge data set a good idea?
  • How can I know if a table is already arranged in ascending order in MySQL?
  • MySQL - Designing database for a simple game
  • Why am I getting "Host '192.168.1.220' is not allowed to connect to this MySQL server"?
  • what type of password hash? possible mysql hash?
  • MySQL - Using a date range vs functions
  • Using IS NULL and COALESCE in OrderBy Doctrine Querybuilder
  • How to merge MySQL columns into one column if there are empty values in the table?
  • Cardinality Confusion
  • Renaming column multiple ids in SELECT
  • Group all from and to messages per user
  • How to handled the null values in WHERE IN condition in mysql
  • Is it okay to update primary key field to shift a record to the top?
  • Stop query through pdo
  • How to check whether particular value in field in MySQL exists
  • Execute a statement for every table in a database
  • insertion 74G data into mysql table cost more then 2 days, how to improve insert performance
  • Where can I see the differents "Hibernate Console Configurations" in Eclipse
  • MySql | relational database vs non relational database in terms of Performance
  • Exporting mysql database using mysqldump including procedures
  • Trigger MySQL not working
  • How do I update values for individual rows quickly?
  • MySQL join query with multiple where condition
  • MySQL stored procedure is not working
  • MySQL - Order By exact match at the end
  • Select max date or null date from same table MySQL
  • Best solution workaround for needing a mysql event on insert?
  • MySQL select several columns of several tables at the same time without using JOIN
  • Is it more efficient to have a table with one of its columns mostly empty or make a new table and refer to it?
  • mysql data truncated with ñ character
  • MySQL Distinct Active Users for the last month query
  • Get all rows that match another attribute in the same table
  • MySQL statement to get min value with max ID
  • DATEDIFF Current/Date for Last Record
  • What is the logic or procedure for combining multiple DB query's results into one elegant table?
  • Modify TIMESTAMP MySQL for use as Primary Key
  • Django - Efficiently bulk create inherited models
  • MySQL Dual table Join Dual table
  • Ruby on Rails - database where sorted by id
  • MySQL 5.6 : Access denied for user 'root' @ 'localhost' when password contains backslash
  • sql query case dateadd
  • shadow
    Privacy Policy - Terms - Contact Us © ourworld-yourmove.org