For an instructor lead, in-depth look at learning SQL click below.
SQL, or Structured Query Language, is the widely used language for interacting with databases. Whether you are a software developer, a data analyst, or anyone dealing with data, understanding SQL is a necessity. This blog post will guide you through the basics of SQL and provide you with practical examples of SQL code. Let’s dive right in!
What is SQL?
SQL is a standard language for managing and manipulating databases. It includes various tasks including insertion, query, update, delete, and data schema creation and modification. SQL helps in managing and organizing data in all sorts of systems in which various data relationships exist.
SQL Syntax
The SQL commands are easy to understand. Let’s have a look at the basic commands in SQL:
SELECT
The SELECT statement is used to select data from a database. Data returned is stored in a result table, called the result-set.
|
1 2 3 |
SELECT column1, column2 FROM table_name |
In this SQL command, column1 and column2 are the fields of a table (table_name), from where we want to fetch the data.
FROM
FROM clause is used to mention the table from which we want to retrieve data.
|
1 2 3 |
SELECT * FROM table_name |
In this SQL command, ‘*’ selects all available fields from the table (table_name).
WHERE
WHERE clause is used to filter records. It is used to extract only those records that fulfill a specified condition.
|
1 2 3 |
SELECT column1, column2 FROM table_name WHERE condition |
In this SQL command, only the data of column1 and column2 will be fetched where a certain condition is met.
UPDATE
UPDATE statement is used to modify the existing records in a table.
|
1 2 3 |
UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition |
In this SQL command, the values of column1 and column2 are updated where a certain condition is met.
DELETE
DELETE statement is used to delete existing records in a table.
|
1 2 3 |
DELETE FROM table_name WHERE condition |
In this SQL command, the row will be deleted from the table where a certain condition is met.
Conclusion
SQL is a powerful language used to communicate with databases, manipulate, and retrieve data. Today we’ve covered the basics, but there’s still a lot more to learn. Remember that mastery comes with continuous practice. Keep challenging yourself with more complex queries to get the feel for using SQL in real-world scenarios.