Trying to return a 2 dimensional table from SQL query (Postgres). Read about Pivot Table (but not sure if it is valid for join) and crosstab/tablefunc but no luck. Expected result App A | …
Tag: inner-join
Hive: randomly select N values from distinct values of one column
Suppose I have a dataset like this I would like to randomly select, say, 3 values from the distinct ID values. One possibility is to get a table like this How shall I do that in Hive? Answer Here is one option using a join and rand(): The subquery randomly selects 3 ids, then the outer query brings all relate…
how to update column with row number in group by result in MySQL
Sample Data: Desire Data: how to write a sql to update the room seat number to serial num in MySQL 5.7? the room’s seat is from 2-20. Answer One option uses the update/join syntax. In MySQL 5.7, where window functions are not available, you can emulate row_number() with a correlated subquery (which is s…
MySQL query for multi-column distinct plus an ancillary column condition
Imagine a flat table that tracks game matches in which each game has three participants: an attacker, a defender and a bettor who is wagering on the outcome of the battle between players 1 and 2. The table includes the names of the players and the bettor of each game, as well as the date of the game, the scor…
SQL Server INNER JOIN and GROUP BY
In sql server I’m trying to group by each sales people some infos as follow: I have 2 tables: Positions and Clients In Positions table, I have the following columns: Client_Id, Balance, Acquisition_Cost and in the Clients table I use the following columns: Client_Id and Sales_person. I want to group by …
How to join two tables in sql according to a determined value?
I have the following tables and I have to get all orders of customer Meier. Table Customer with columns cid and name: cid name ————————- 13 M. Mueller 17 …
inner join with subquery results differs for these data sets
CREATE TABLE IF NOT EXISTS `wcd` ( `id` int(6) unsigned NOT NULL, `wid` int(11) unsigned NOT NULL, PRIMARY KEY (`id`) ) DEFAULT CHARSET=utf8; INSERT INTO `wcd` (`id`, `wid`) VALUES (‘168’, ‘…
How to calculate aggregate on inner join
I have two tables, Post & Comment. Post table contains info about posts & comment table contains the comments data about each post. Below is there structure, I need to take post_id, post_title from post table and total no of comments (using aggregate function count) on each post from comment table &am…
Order of tables in INNER JOIN
Going through a book, Learning SQL by Alan Beaulieu. On topic of inner joins, it tells that whatever be the order of tables in a INNER JOIN, results are same and gives reason as follows: If you are confused about why all three versions of the account/employee/customer query yield the same results, keep in min…
Write a query to display the student names and the maximum mark scored by them in any subject
I have tried using group by and getting an error message of single row function cannot return multiple values. It has three tables to be selected student, subject and mark.