Data Analytics and Video Tutorials
Selecting a column is used in SQL to retrieve records from a table provided that the column name exists.
In SQL, a unique key is a constraint that ensures that the values in a column or set of columns are unique across all rows in a table and that the values cannot be null. A unique key is similar to a primary key, but it differs in that it does not necessarily need to…
In SQL, constraints are rules that are enforced on a table’s data to maintain the integrity and accuracy of the data. Constraints can be applied to one or more columns in a table, and they can be added or removed as needed. Here are some of the most common types of constraints in SQL: Constraints…
Building on how to select all records with SQL , you may want to learn how to get specific columns of data from your table. Using SQLite again , we will now look to select two columns from the table below, namely name and iso_code. The purpose of completing this, is to allow the user…