I'd like to understand why the following 2 queries that select duplicates from the companies table have different execution times. The second query with the JOIN is executed much faster. The query is executed on: a companies table with ~200k…
Write a solution to find the second highest salary from the Employee table. If there is no second highest salary, return null. This is my code: select ifnull(x.salary,NULL) as SecondHighestSalary from( select *, dense_rank() over( order by salary) as rnk…
There are 4 tables: trunk, branch, leaf and data. The Trunk table has an IDTrunk and TrunkNumber columns. The Branch table has an IDBranch, IDTrunk and BranchNumber columns. The leaf table has a IDLeaf, IDBranch and a LeafNumber columns. The…
There are numerous SQL questions and answers about finding gaps in sequences, but I could not find any that have the wrinkle my situation has: I need to group the sequence by another column. My table (simplified) id | parent_id…
I'm facing a problem where my syntax in PhpMyAdmin got an error this is my code CREATE PROCEDURE `tambah_semua`(IN `Nama` VARCHAR(255), IN `Plat_Nomor` VARCHAR(8), IN `Deskripsi` TEXT, IN `Total` INT) NOT DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER INSERT INTO `User`…
I have a MySQL table having "datetime" columns begintime and endtime: +---------------------+---------------------+ | begintime | endtime | +---------------------+---------------------+ | 2024-05-22 10:13:23 | 2024-05-31 13:37:34 | | 2024-05-30 17:03:21 | 2024-05-31 16:01:25 | | 2024-05-30 17:03:21 | 2024-05-31 16:01:25 | |…
I have a table employees as below: id name managerId 1 Annie Null 2 Bob Null 3 Chloe 1 4 Danny 2 5 Eddie 3 6 Felicia 3 7 Georgia 4 8 Harper 3 Top-level management is Annie and Bob…
In MySQL 5.7.25 and MariaDB 10.6.15, using InnoDB by default to create below table create table t1( id serial, employee_id int not null, name varchar(20), status tinyint, created_at datetime(3) not null, updated_at datetime(3) not null, event CHAR not null, primary…
I'm essentially doing an ETL on a large SQL table. I need to pull rows, perform a calculation, then write them back to the same server but a different table. What I'm seeing is workChannel fill up then everything stops.…
I'm using MySQL 8.0.35 and I've two tables in my database: users and clients. Users can be searched by username, firstname, lastname, email, phone, document or even id. The clients table is used to track which users are clients of…