SQL – Page 491 – SQL Questions Answer

Can’t alter column type to a shorter VARCHAR in Redshift. Getting “target column size should be greater or equal to current maximum column size”

I’m trying to run in Amazon Redshift, but I’m getting this error: SQL Error [500310] [0A000]: Amazon Invalid operation: cannot alter column “column_name” of relation “table_name”, target column size 256 should be greater or equal to current maximum column size 879; I’…

How to drop duplicate rows from postgresql sql table

duplicates postgresql sql sql-delete

I have the following dataset in a postgresql table called testtable in testdb. I have accidentally copied over the database and duplicated rows. How can I delete the duplicates? Row 1 and row 5 are copies in this frame and row 2 and row 4 are copies too. I have never used sql before to drop duplicates I have …

Delete record from table if certain fields are empty upon closing a Form

ms-access sql vba

I am trying to get a button to close a Form and at the same time delete records on a table where certain fields are empty. I have this on the Form: AlimentoporTanque is the Table’s name and Tanques and Alimento the fields that should not be empty. When I click on the button I get following MsbBox poppin…

How to compare two sets in MySQL or SQL SERVER?

In this University Database: CREATE TABLE Stud( [S#] INT PRIMARY KEY, Sname NVARCHAR(50), City NVARCHAR(50), GPA FLOAT, [Clg#] SMALLINT ); CREATE TABLE Sec( [Sec#] SMALLINT, …

Canonical way to store reciprocal data sql

mysql relational-database sql

I got a lot of instances of the same Class. Now these objects can be linked and this link can have a weight. Like in an undirected graph. Now I want to store the relationship between each two objects in my mysql database. Data looks like this I could do create a table with this structure: object1_id | object2…

How to select distinct value from multiple tables given a column filter?

distinct sql sql-server

I have this table Products Id ProductName ProductCode 1 Alexa P0001 2 Alexa P0002 3 Alexa 2 P0003 4 Aquarium P0004 5 Aquarium X P0004 6 Bathtub P0005 Scenario 1: Expected Result: Returns distinct ProductName along with Id Id ProductName 1 Alexa 3 Alexa 2 4 Aquarium 5 Aquarium X Actual result: Returns all prod…

Using the Union function in SQL to reverse columns

sql sql-server

I have the following SQL code to produce the following table of data: I am hoping to transform data to create a table that looks like: What would be the best way to achieve this? Something like creating two tables and then a Union join? Answer You can use self join to achieve what are you looking for. Schema:…