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If you’re new to the world of SQL (Structured Query Language) and data analytics, getting started can seem like a daunting task. But, don’t fret! This introductory blog post will cover the essential tools and skills you’ll need to get started with SQL, one of the most prevalent and powerful programming languages used by data professionals today, complete with examples of SQL code.
Understanding SQL & Its Importance
SQL is a specialized programming language used to manage and manipulate databases. It is used to insert, search, update, delete and alter database records. In an era driven by information and data, understanding SQL is a vital skill for data analysts, data scientists, and anyone seeking to retrieve or manage data from a relational database management system.
A Basic SQL Query
SQL commands are incredibly versatile. Here’s an example of a basic SQL command that retrieves data from a database:
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SELECT * FROM Employees; |
In this example, SELECT * FROM Employees; is a command that tells your database you want to fetch (or SELECT) all records (*) from the ‘Employees’ Table.
The SQL SELECT Statement
The SELECT statement is probably the most commonly used SQL command. This command is used to select data from a database. The data returned is stored in a result table, called the result-set.
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SELECT column1, column2 FROM table_name; |
In this example, column1 and column2 are the names of the columns you want to select data from.
Combining SQL Statements
You can also use SQL queries to filter and order your data. For instance, the following query selects only the employees making more than $60000:
Filtering With the WHERE Statement
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SELECT * FROM Employees WHERE salary > 60000; |
Sorting With the ORDER BY Statement
The ORDER BY statement orders the result-set by one or more columns. It sorts the records in ascending order by default. To sort the records in descending order, use the DESC keyword.
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SELECT * FROM Employees ORDER BY salary DESC; |
Starting off with SQL can indeed be quite daunting, but with a bit of patience and a lot of practice, you’ll find yourself writing complex queries in no time. Remember, the key to learning SQL is practice. So, don’t be afraid of making mistakes, and happy querying!