Data Analytics and Video Tutorials
Use SQL or structured query language to write code to create, read, update and delete data into a database table, which can then be retrieved at a later stage.
DROP and TRUNCATE are two SQL commands that can be used to remove data from a table, but they work in different ways: How to drop a table from a database It is important to remember that if you have the same name spread over a few databases, you should reference the correct databases, to…
Read More “What is the difference between DROP and TRUNCATE in SQL?” »
Query optimization in SQL refers to the process of improving the performance of SQL queries by selecting the most efficient execution plan for the query. When a SQL query is executed, the database management system (DBMS) must determine the best way to retrieve the requested data from the database. Query optimization involves analyzing the query…
In SQL, a clustered index is a type of index that determines the physical order of the data in a table. It organizes the table data based on the values in one or more columns, and stores the data in the table accordingly. When a clustered index is created on a table, the rows of…
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…
SQL(Structured Query Language) and MySQL are related but distinct concepts. SQL is a programming language that is used to manage relational databases, while MySQL is a specific relational database management system (RDBMS) that uses SQL as its query language. Here are some key differences between SQL and MySQL: In summary, SQL is a language used…
CTE stands for Common Table Expression, and it is a temporary named result set that you can reference within a SQL statement. A CTE is defined within a query and is available only for the duration of that query. It allows you to create a named temporary table that you can reference multiple times within…
You have been probably looking at large sets of data for a while, and projects to extract insights from them. If you are given a set of data that is so large you may need something more! This is where Apache Spark comes in! So what does Apache Spark do? It performs the following functions:…
There are multiple reasons for wanting to update records in a database table, from data quality to enriching your data for any machine learning projects. One example maybe where you want to add a creation date to a record. In this blog post we will look at how to update database records, and also where…