Master SQL step-by-step! From basics to advanced, here are the key topics you need for a solid SQL foundation. 🚀
1. Foundations:
- Learn basic SQL syntax, including SELECT, FROM, WHERE clauses.
- Understand data types, constraints, and the basic structure of a database.
2. Database Design:
- Study database normalization to ensure efficient data organization.
- Learn about primary keys, foreign keys, and relationships between tables.
3. Queries and Joins:
- Practice writing simple to complex SELECT queries.
- Master different types of joins (INNER, LEFT, RIGHT, FULL) to combine data from multiple tables.
4. Aggregation and Grouping:
- Explore aggregate functions like COUNT, SUM, AVG, MAX, and MIN.
- Understand GROUP BY clause for summarizing data based on specific criteria.
5. Subqueries and Nested Queries:
- Learn how to use subqueries to perform operations within another query.
- Understand the concept of nested queries and their practical applications.
6. Indexing and Optimization:
- Study indexing for enhancing query performance.
- Learn optimization techniques, such as avoiding SELECT * and using appropriate indexes.
7. Transactions and ACID Properties:
- Understand the basics of transactions and their role in maintaining data integrity.
- Explore ACID properties (Atomicity, Consistency, Isolation, Durability) in database management.
8. Views and Stored Procedures:
- Create and use views to simplify complex queries.
- Learn about stored procedures for reusable and efficient query execution.
9. Security and Permissions:
- Understand SQL injection risks and how to prevent them.
- Learn how to manage user permissions and access control.
10. Advanced Topics:
- Explore advanced SQL concepts like window functions, CTEs (Common Table Expressions), and recursive queries.
- Familiarize yourself with database-specific features (e.g., PostgreSQL's JSON functions, MySQL's spatial data types).
11. Real-world Projects:
- Apply your knowledge to real-world scenarios by working on projects.
- Practice with sample databases or create your own to reinforce your skills.
12. Continuous Learning:
- Stay updated on SQL advancements and industry best practices.
- Engage with online communities, forums, and resources for ongoing learning and problem-solving.
Here are some free resources to learn & practice SQL 👇👇
Udacity free course- https://imp.i115008.net/AoAg7K
SQL For Data Analysis: https://t.me/sqlanalyst
For Practice- https://stratascratch.com/?via=free
SQL Learning Series: https://t.me/sqlspecialist/567
Top 10 SQL Projects with Datasets: https://t.me/DataPortfolio/16
Join for more free resources: https://t.me/free4unow_backup
ENJOY LEARNING 👍👍
1. Foundations:
- Learn basic SQL syntax, including SELECT, FROM, WHERE clauses.
- Understand data types, constraints, and the basic structure of a database.
2. Database Design:
- Study database normalization to ensure efficient data organization.
- Learn about primary keys, foreign keys, and relationships between tables.
3. Queries and Joins:
- Practice writing simple to complex SELECT queries.
- Master different types of joins (INNER, LEFT, RIGHT, FULL) to combine data from multiple tables.
4. Aggregation and Grouping:
- Explore aggregate functions like COUNT, SUM, AVG, MAX, and MIN.
- Understand GROUP BY clause for summarizing data based on specific criteria.
5. Subqueries and Nested Queries:
- Learn how to use subqueries to perform operations within another query.
- Understand the concept of nested queries and their practical applications.
6. Indexing and Optimization:
- Study indexing for enhancing query performance.
- Learn optimization techniques, such as avoiding SELECT * and using appropriate indexes.
7. Transactions and ACID Properties:
- Understand the basics of transactions and their role in maintaining data integrity.
- Explore ACID properties (Atomicity, Consistency, Isolation, Durability) in database management.
8. Views and Stored Procedures:
- Create and use views to simplify complex queries.
- Learn about stored procedures for reusable and efficient query execution.
9. Security and Permissions:
- Understand SQL injection risks and how to prevent them.
- Learn how to manage user permissions and access control.
10. Advanced Topics:
- Explore advanced SQL concepts like window functions, CTEs (Common Table Expressions), and recursive queries.
- Familiarize yourself with database-specific features (e.g., PostgreSQL's JSON functions, MySQL's spatial data types).
11. Real-world Projects:
- Apply your knowledge to real-world scenarios by working on projects.
- Practice with sample databases or create your own to reinforce your skills.
12. Continuous Learning:
- Stay updated on SQL advancements and industry best practices.
- Engage with online communities, forums, and resources for ongoing learning and problem-solving.
Here are some free resources to learn & practice SQL 👇👇
Udacity free course- https://imp.i115008.net/AoAg7K
SQL For Data Analysis: https://t.me/sqlanalyst
For Practice- https://stratascratch.com/?via=free
SQL Learning Series: https://t.me/sqlspecialist/567
Top 10 SQL Projects with Datasets: https://t.me/DataPortfolio/16
Join for more free resources: https://t.me/free4unow_backup
ENJOY LEARNING 👍👍
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Why learn SQL if ChatGPT can write it?
A few reasons why you should still learn SQL:
1️⃣ An understanding of the nuances of SQL is necessary to ask the Large Language Model (”LLM”) the right questions to get a good response.
2️⃣ You have to double check the LLMs response. Sometimes I get answers that uses features that have been deprecated (probably because the LLM was trained on older data). It still makes mistakes and overcomplicates problems.
3️⃣ Making changes to the query requires an understanding of SQL. Without it, you might get stuck. It's important to understand the query's purpose.
So what do I use these LLMs for?
I find it a good starting point for syntax or query structure. Like “how would I use a window function to get the latest record in a table?” But it doesn’t understand my company’s data models, table relationships, or business logic. This is where my SQL + business knowledge comes in.
A few reasons why you should still learn SQL:
1️⃣ An understanding of the nuances of SQL is necessary to ask the Large Language Model (”LLM”) the right questions to get a good response.
2️⃣ You have to double check the LLMs response. Sometimes I get answers that uses features that have been deprecated (probably because the LLM was trained on older data). It still makes mistakes and overcomplicates problems.
3️⃣ Making changes to the query requires an understanding of SQL. Without it, you might get stuck. It's important to understand the query's purpose.
So what do I use these LLMs for?
I find it a good starting point for syntax or query structure. Like “how would I use a window function to get the latest record in a table?” But it doesn’t understand my company’s data models, table relationships, or business logic. This is where my SQL + business knowledge comes in.
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What's the difference between IS NULL and = 'NULL'?
NULL means no value.
'NULL' is a string "NULL".
They look similar but behave very differently.
In SQL, NULL is not a value.
It's a lack of a value.
So, when you use IS NULL, you’re asking for records where that field has no value.
When you use = 'NULL', you’re asking for records where that field has the value of the string 'NULL'.
NULL means no value.
'NULL' is a string "NULL".
They look similar but behave very differently.
In SQL, NULL is not a value.
It's a lack of a value.
So, when you use IS NULL, you’re asking for records where that field has no value.
When you use = 'NULL', you’re asking for records where that field has the value of the string 'NULL'.
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📊🚀A beginner's roadmap for learning SQL:
🔹Understand Basics:
Learn what SQL is and its purpose in managing relational databases.
Understand basic database concepts like tables, rows, columns, and relationships.
🔹Learn SQL Syntax:
Familiarize yourself with SQL syntax for common commands like SELECT, INSERT, UPDATE, DELETE.
Understand clauses like WHERE, ORDER BY, GROUP BY, and JOIN.
🔹Setup a Database:
Install a relational database management system (RDBMS) like MySQL, SQLite, or PostgreSQL.
Practice creating databases, tables, and inserting data.
🔹Retrieve Data (SELECT):
Learn to retrieve data from a database using SELECT statements.
Practice filtering data using WHERE clause and sorting using ORDER BY.
🔹Modify Data (INSERT, UPDATE, DELETE):
Understand how to insert new records, update existing ones, and delete data.
Be cautious with DELETE to avoid unintentional data loss.
🔹Working with Functions:
Explore SQL functions like COUNT, AVG, SUM, MAX, MIN for data analysis.
Understand string functions, date functions, and mathematical functions.
🔹Data Filtering and Sorting:
Learn advanced filtering techniques using AND, OR, and IN operators.
Practice sorting data using multiple columns.
🔹Table Relationships (JOIN):
Understand the concept of joining tables to retrieve data from multiple tables.
Learn about INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.
🔹Grouping and Aggregation:
Explore GROUP BY clause to group data based on specific columns.
Understand aggregate functions for summarizing data (SUM, AVG, COUNT).
🔹Subqueries:
Learn to use subqueries to perform complex queries.
Understand how to use subqueries in SELECT, WHERE, and FROM clauses.
🔹Indexes and Optimization:
Gain knowledge about indexes and their role in optimizing queries.
Understand how to optimize SQL queries for better performance.
🔹Transactions and ACID Properties:
Learn about transactions and the ACID properties (Atomicity, Consistency, Isolation, Durability).
Understand how to use transactions to maintain data integrity.
🔹Normalization:
Understand the basics of database normalization to design efficient databases.
Learn about 1NF, 2NF, 3NF, and BCNF.
🔹Backup and Recovery:
Understand the importance of database backups.
Learn how to perform backups and recovery operations.
🔹Practice and Projects:
Apply your knowledge through hands-on projects.
Practice on platforms like LeetCode, HackerRank, or build your own small database-driven projects.
👀👍Remember to practice regularly and build real-world projects to reinforce your learning. Happy coding!
🔹Understand Basics:
Learn what SQL is and its purpose in managing relational databases.
Understand basic database concepts like tables, rows, columns, and relationships.
🔹Learn SQL Syntax:
Familiarize yourself with SQL syntax for common commands like SELECT, INSERT, UPDATE, DELETE.
Understand clauses like WHERE, ORDER BY, GROUP BY, and JOIN.
🔹Setup a Database:
Install a relational database management system (RDBMS) like MySQL, SQLite, or PostgreSQL.
Practice creating databases, tables, and inserting data.
🔹Retrieve Data (SELECT):
Learn to retrieve data from a database using SELECT statements.
Practice filtering data using WHERE clause and sorting using ORDER BY.
🔹Modify Data (INSERT, UPDATE, DELETE):
Understand how to insert new records, update existing ones, and delete data.
Be cautious with DELETE to avoid unintentional data loss.
🔹Working with Functions:
Explore SQL functions like COUNT, AVG, SUM, MAX, MIN for data analysis.
Understand string functions, date functions, and mathematical functions.
🔹Data Filtering and Sorting:
Learn advanced filtering techniques using AND, OR, and IN operators.
Practice sorting data using multiple columns.
🔹Table Relationships (JOIN):
Understand the concept of joining tables to retrieve data from multiple tables.
Learn about INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.
🔹Grouping and Aggregation:
Explore GROUP BY clause to group data based on specific columns.
Understand aggregate functions for summarizing data (SUM, AVG, COUNT).
🔹Subqueries:
Learn to use subqueries to perform complex queries.
Understand how to use subqueries in SELECT, WHERE, and FROM clauses.
🔹Indexes and Optimization:
Gain knowledge about indexes and their role in optimizing queries.
Understand how to optimize SQL queries for better performance.
🔹Transactions and ACID Properties:
Learn about transactions and the ACID properties (Atomicity, Consistency, Isolation, Durability).
Understand how to use transactions to maintain data integrity.
🔹Normalization:
Understand the basics of database normalization to design efficient databases.
Learn about 1NF, 2NF, 3NF, and BCNF.
🔹Backup and Recovery:
Understand the importance of database backups.
Learn how to perform backups and recovery operations.
🔹Practice and Projects:
Apply your knowledge through hands-on projects.
Practice on platforms like LeetCode, HackerRank, or build your own small database-driven projects.
👀👍Remember to practice regularly and build real-world projects to reinforce your learning. Happy coding!
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1. List the different types of relationships in SQL.
One-to-One - This can be defined as the relationship between two tables where each record in one table is associated with the maximum of one record in the other table.
One-to-Many & Many-to-One - This is the most commonly used relationship where a record in a table is associated with multiple records in the other table.
Many-to-Many - This is used in cases when multiple instances on both sides are needed for defining a relationship.
Self-Referencing Relationships - This is used when a table needs to define a relationship with itself.
2. What are the different views available in Power BI Desktop?
There are three different views in Power BI, each of which serves another purpose:
Report View - In this view, users can add visualizations and additional report pages and publish the same on the portal.
Data View - In this view, data shaping can be performed using Query Editor tools.
Model View - In this view, users can manage relationships between complex datasets.
3. What are macros in Excel?
Excel allows you to automate the tasks you do regularly by recording them into macros. So, a macro is an action or a set of them that you can perform n number of times. For example, if you have to record the sales of each item at the end of the day, you can create a macro that will automatically calculate the sales, profits, loss, etc and use the same for the future instead of manually calculating it every day.
One-to-One - This can be defined as the relationship between two tables where each record in one table is associated with the maximum of one record in the other table.
One-to-Many & Many-to-One - This is the most commonly used relationship where a record in a table is associated with multiple records in the other table.
Many-to-Many - This is used in cases when multiple instances on both sides are needed for defining a relationship.
Self-Referencing Relationships - This is used when a table needs to define a relationship with itself.
2. What are the different views available in Power BI Desktop?
There are three different views in Power BI, each of which serves another purpose:
Report View - In this view, users can add visualizations and additional report pages and publish the same on the portal.
Data View - In this view, data shaping can be performed using Query Editor tools.
Model View - In this view, users can manage relationships between complex datasets.
3. What are macros in Excel?
Excel allows you to automate the tasks you do regularly by recording them into macros. So, a macro is an action or a set of them that you can perform n number of times. For example, if you have to record the sales of each item at the end of the day, you can create a macro that will automatically calculate the sales, profits, loss, etc and use the same for the future instead of manually calculating it every day.
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Essential SQL Topics for Data Analysts
SQL for Data Analysts Free Resources -> https://t.me/sqlanalyst
- Basic Queries: SELECT, FROM, WHERE clauses.
- Sorting and Filtering: ORDER BY, GROUP BY, HAVING.
- Joins: INNER JOIN, LEFT JOIN, RIGHT JOIN.
- Aggregation Functions: COUNT, SUM, AVG, MIN, MAX.
- Subqueries: Embedding queries within queries.
- Data Modification: INSERT, UPDATE, DELETE.
- Indexes: Optimizing query performance.
- Normalization: Ensuring efficient database design.
- Views: Creating virtual tables for simplified queries.
- Understanding Database Relationships: One-to-One, One-to-Many, Many-to-Many.
Window functions are also important for data analysts. They allow for advanced data analysis and manipulation within specified subsets of data. Commonly used window functions include:
- ROW_NUMBER(): Assigns a unique number to each row based on a specified order.
- RANK() and DENSE_RANK(): Rank data based on a specified order, handling ties differently.
- LAG() and LEAD(): Access data from preceding or following rows within a partition.
- SUM(), AVG(), MIN(), MAX(): Aggregations over a defined window of rows.
Here is an amazing resources to learn & practice SQL: https://bit.ly/3FxxKPz
Share with credits: https://t.me/sqlspecialist
Hope it helps :)
SQL for Data Analysts Free Resources -> https://t.me/sqlanalyst
- Basic Queries: SELECT, FROM, WHERE clauses.
- Sorting and Filtering: ORDER BY, GROUP BY, HAVING.
- Joins: INNER JOIN, LEFT JOIN, RIGHT JOIN.
- Aggregation Functions: COUNT, SUM, AVG, MIN, MAX.
- Subqueries: Embedding queries within queries.
- Data Modification: INSERT, UPDATE, DELETE.
- Indexes: Optimizing query performance.
- Normalization: Ensuring efficient database design.
- Views: Creating virtual tables for simplified queries.
- Understanding Database Relationships: One-to-One, One-to-Many, Many-to-Many.
Window functions are also important for data analysts. They allow for advanced data analysis and manipulation within specified subsets of data. Commonly used window functions include:
- ROW_NUMBER(): Assigns a unique number to each row based on a specified order.
- RANK() and DENSE_RANK(): Rank data based on a specified order, handling ties differently.
- LAG() and LEAD(): Access data from preceding or following rows within a partition.
- SUM(), AVG(), MIN(), MAX(): Aggregations over a defined window of rows.
Here is an amazing resources to learn & practice SQL: https://bit.ly/3FxxKPz
Share with credits: https://t.me/sqlspecialist
Hope it helps :)
👍13❤2🎉2
Forwarded from Data Analytics
Many people pay too much to learn SQL, but my mission is to break down barriers. I have shared complete learning series to learn SQL from scratch.
Here are the links to the SQL series
Complete SQL Topics for Data Analyst: https://t.me/sqlspecialist/523
Part-1: https://t.me/sqlspecialist/524
Part-2: https://t.me/sqlspecialist/525
Part-3: https://t.me/sqlspecialist/526
Part-4: https://t.me/sqlspecialist/527
Part-5: https://t.me/sqlspecialist/529
Part-6: https://t.me/sqlspecialist/534
Part-7: https://t.me/sqlspecialist/534
Part-8: https://t.me/sqlspecialist/536
Part-9: https://t.me/sqlspecialist/537
Part-10: https://t.me/sqlspecialist/539
Part-11: https://t.me/sqlspecialist/540
Part-12:
https://t.me/sqlspecialist/541
Part-13: https://t.me/sqlspecialist/542
Part-14: https://t.me/sqlspecialist/544
Part-15: https://t.me/sqlspecialist/545
Part-16: https://t.me/sqlspecialist/546
Part-17: https://t.me/sqlspecialist/549
Part-18: https://t.me/sqlspecialist/552
Part-19: https://t.me/sqlspecialist/555
Part-20: https://t.me/sqlspecialist/556
I saw a lot of big influencers copy pasting my content after removing the credits. It's absolutely fine for me as more people are getting free education because of my content.
But I will really appreciate if you share credits for the time and efforts I put in to create such valuable content. I hope you can understand.
Complete Python Topics for Data Analysts: https://t.me/sqlspecialist/548
Complete Excel Topics for Data Analysts: https://t.me/sqlspecialist/547
I'll continue with learning series on Python, Power BI, Excel & Tableau.
Thanks to all who support our channel and share the content with proper credits. You guys are really amazing.
Hope it helps :)
Here are the links to the SQL series
Complete SQL Topics for Data Analyst: https://t.me/sqlspecialist/523
Part-1: https://t.me/sqlspecialist/524
Part-2: https://t.me/sqlspecialist/525
Part-3: https://t.me/sqlspecialist/526
Part-4: https://t.me/sqlspecialist/527
Part-5: https://t.me/sqlspecialist/529
Part-6: https://t.me/sqlspecialist/534
Part-7: https://t.me/sqlspecialist/534
Part-8: https://t.me/sqlspecialist/536
Part-9: https://t.me/sqlspecialist/537
Part-10: https://t.me/sqlspecialist/539
Part-11: https://t.me/sqlspecialist/540
Part-12:
https://t.me/sqlspecialist/541
Part-13: https://t.me/sqlspecialist/542
Part-14: https://t.me/sqlspecialist/544
Part-15: https://t.me/sqlspecialist/545
Part-16: https://t.me/sqlspecialist/546
Part-17: https://t.me/sqlspecialist/549
Part-18: https://t.me/sqlspecialist/552
Part-19: https://t.me/sqlspecialist/555
Part-20: https://t.me/sqlspecialist/556
I saw a lot of big influencers copy pasting my content after removing the credits. It's absolutely fine for me as more people are getting free education because of my content.
But I will really appreciate if you share credits for the time and efforts I put in to create such valuable content. I hope you can understand.
Complete Python Topics for Data Analysts: https://t.me/sqlspecialist/548
Complete Excel Topics for Data Analysts: https://t.me/sqlspecialist/547
I'll continue with learning series on Python, Power BI, Excel & Tableau.
Thanks to all who support our channel and share the content with proper credits. You guys are really amazing.
Hope it helps :)
👍37❤12😍4👏2🎉1
After you've learned the basics of SQL (SELECT, FROM, WHERE), you can focus on...
- LEFT/INNER JOINs
- aggregate functions
- date & time functions
- CASE WHEN statements
- CTEs/subqueries/temp tables
and from there...
- triggers
- recursive CTEs
- window functions
- stored procedures
- query optimization
- LEFT/INNER JOINs
- aggregate functions
- date & time functions
- CASE WHEN statements
- CTEs/subqueries/temp tables
and from there...
- triggers
- recursive CTEs
- window functions
- stored procedures
- query optimization
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Learning SQL?
It doesn't have to be so hard!
Start with the Big 6...
1. SELECT
2. FROM
3. WHERE
4. GROUP BY
5. HAVING
6. ORDER BY
It doesn't have to be so hard!
Start with the Big 6...
1. SELECT
2. FROM
3. WHERE
4. GROUP BY
5. HAVING
6. ORDER BY
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Got an Interview tomorrow? Want to practice SQL & Python online?
Applying to jobs every day is great, but remember to practice too! When you get an interview unexpectedly, you'll be well-prepared and ready to shine!
Here are a some websites that can help you with practice and cracking the interviews:
https://www.linkedin.com/posts/sql-analysts_got-an-interview-tomorrow-want-to-practice-activity-7218187268685983744-W5KC
Like for more content like this ❤️
Applying to jobs every day is great, but remember to practice too! When you get an interview unexpectedly, you'll be well-prepared and ready to shine!
Here are a some websites that can help you with practice and cracking the interviews:
https://www.linkedin.com/posts/sql-analysts_got-an-interview-tomorrow-want-to-practice-activity-7218187268685983744-W5KC
Like for more content like this ❤️
❤5👍2