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Welcome to SQL 101, an instructional guide designed to introduce beginners to the fascinating world of SQL (Structured Query Language). SQL is the standard language for managing and manipulating databases, and mastering it is crucial for anyone interested in handling data professionally.
What is SQL?
SQL, pronounced as “S-Q-L” or “sequel”, is a language used to communicate with databases. It is a standard language for creating, querying, updating, and managing relational database systems. It includes a variety of elements including clauses, expressions, queries, and statements, which help in task performance like update data in a database or retrieve data from a database.
Understanding Basic SQL Syntax
Let’s dive into some basic SQL commands. SQL commands can be divided into a few major types: Data Definition Language (DDL), Data Manipulation Language (DML), and Data Control Language (DCL). For starters, we’ll focus on the two most commonly used SQL commands: SELECT and FROM.
SELECT Command
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SELECT column1, column2, ... FROM table_name; |
Here, we’re using the SELECT statement followed by the column names to select data from a database. The SELECT statement is used to select data from a database, and the data returned is stored in a ‘result table’, also called the result-set.
FROM Command
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SELECT column1, column2, ... FROM table_name; |
In these lines of SQL command, column1, column2, … are the field names of the table you want to select data from. If you want to select all the fields available in the table, use the following syntax:
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SELECT * FROM table_name; |
Working with WHERE Clause
The WHERE clause is used to filter records. It is used to extract only those records that fulfil a specified condition.
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SELECT column1, column2, ... FROM table_name WHERE condition; |
Conclusion
Hopefully, this quick glimpse into SQL has given you an understanding of what it’s all about. Learning SQL can open up new opportunities for you in the data handling and analytics industry. Remember, the above examples are only the basic SQL commands. A lot more can be achieved with SQL. So, keep practicing!
We’ll be back with more advanced guides soon. Stay tuned!
Sources:
W3Schools
SQL Server Microsoft Documentation