greatest-n-per-group

SCHEMA I have the following set-up in MySQL database: CREATE TABLE items ( id SERIAL, name VARCHAR(100), group_id INT, price DECIMAL(10,2), KEY items_group_id_idx (group_id), PRIMARY KEY (id) ); INSERT INTO items VALUES (1, 'Item A', NULL, 10), (2, 'Item B', NULL, 20), (3, 'Item C', NULL, 30), (4, 'Item D', 1, 40), (5, 'Item E', 2, 50), (6, 'Item F', 2, 60), (7, 'Item G', 2, 70); PROBLEM I need to select: All items with group_id that has NULL value, and One item from each group identified by group_id having the lowest price. EXPECTED RESULTS +----+--------+----------+-------+ | id | name |

what is the query to return Name and Salary of employee Having Max Salary SELECT Name, Salary FROM Minions WHERE Salary = (SELECT Max(Salary) FROM Minions) Note that this will return more than one row if there is more than one employee who have the same max salary select name, salary from (select * from salary_table order by salary desc limit 1) arpit SELECT FirstName, max(salary) FROM Employees WHERE salary = ( SELECT max(salary) FROM employees ) GROUP BY FirstName working in SQL SERVER 2012 Select e.name, e.salary from employee e where not exists (select salary from employee e1 where e

I have a table with rows like: id group_name_code 1 999 2 16 3 789 4 999 5 231 6 999 7 349 8 16 9 819 10 999 11 654 But I want output rows like this: id group_name_code 1 999 2 16 3 789 4 231 5 349 6 819 7 654 Will this query help? select id, distinct(group_name_code) from group_table; Erwin Brandstetter You seem to want: Distinct values for group_name_code and a sequential id ordered by minimum id per set of group_name_code . Netezza has the DISTINCT key word, but not DISTINCT ON () (Postgres feature) : https://www.ibm.com/support/knowledgecenter/en/SSULQD_7.2.1/com.ibm.nz.dbu.doc/r_dbuser

I'm working with PHP and PDO, and I need to recolect information joining 3 tables: photos albums album_photos The table have the following structure: photos: photo_id (int) path (varchar) nick (varchar) date (timestamp) albums album_id (int) album_name (varchar) nick (varchar) date (timestamp) album_photos album_id (int) photo_id (int) nick (varchar) date (timestamp) So, I want to show all the albums with a max of 5 photos for each one, where the user nick is 'owner' . To be shown as follows: album_name_1: [photo_1] [photo_2] [photo_3] [photo_4] [photo_5] album_name_2: [photo_1] [photo_2]

I'm not a database guru and feel like I'm missing some core SQL knowledge to grok a solution to this problem. Here's the situation as briefly as I can explain it. Context: I have a SQLite database table that contains timestamped user event records. The records can be uniquely identified by the combination of timestamp and user ID (i.e., when the event took place and who the event is about). I understand this situation is called a "composite primary key." The table looks something like this (with a bunch of other columns removed, of course): sqlite> select Last_Updated,User_ID from records