For an instructor lead, in-depth look at learning SQL click below.
Structured Query Language (SQL) is a standard Database language which is used to create, maintain, and retrieve the relational database. It is particularly useful in handling structured data, i.e., data incorporating relationships among entities and variables.
Here is your step-by-step guide to understanding SQL as a beginner:
1. Understand What is SQL?
SQL stands for Structured Query Language. It is a standard language for dealing with relational databases. SQL programming can be effectively used to insert, search, update, delete database records. That doesn’t mean SQL cannot do things beyond that. In fact, it can do a lot of functions including, but not limited to, optimizing and maintenance of databases.
2. Basic SQL commands
Below are basic SQL commands that are needed to execute queries in the database:
– SELECT
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SELECT column_name FROM table_name |
– DELETE
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DELETE FROM table_name WHERE condition |
– INSERT INTO
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INSERT INTO table_name (column1, column2, column3 ...) VALUES (value1, value2, value3 ...) |
– UPDATE
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UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition |
3. Establish a Connection to a Database
You cannot execute any SQL queries if you can’t connect to a database. Your database could be MySQL, Oracle, SQL Server, etc. You will need a server to host this database.
4. Execute SQL Queries on a Database
Once you have connected to the database, you can execute SQL queries using any language. Below is an example of executing a SQL query in Python:
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import psycopg2 try: conn = psycopg2.connect( database='your_database', user='your_username', password='your_password', host='localhost', port= '5432' ) cur = conn.cursor() cur.execute("SELECT * FROM your_table") rows = cur.fetchall() for row in rows: print(row) except (Exception, psycopg2.DatabaseError) as error : print ("Error while connecting to PostgreSQL", error) finally: if(conn): cur.close() conn.close() print("PostgreSQL connection is closed") |
5. Practice, Practice, Practice
The only way to learn SQL thoroughly is by practicing. Work on mini-projects, solve problems, and try to implement SQL logic to these problems. That’s the best way to learn SQL.
Conclusion
While it may seem like a lot to learn, SQL is a powerful tool for manipulating data and is a skill that is in high demand in many industries. Start small, learn the basics, get your hands dirty with coding, and soon, you’ll be writing queries like a pro!
Happy Learning!