SQL is easy to learn, but difficult to master.
Here are 5 hacks to level up your SQL ๐
1. Know complex joins
2. Master Window functions
3. Explore alternative solutions
4. Master query optimization
5. Get familiar with ETL
โโโ
๐๐ต๐ธ, ๐ต๐ฉ๐ฆ๐ณ๐ฆ ๐ข๐ณ๐ฆ ๐ฑ๐ณ๐ข๐ค๐ต๐ช๐ค๐ฆ ๐ฑ๐ณ๐ฐ๐ฃ๐ญ๐ฆ๐ฎ๐ด ๐ช๐ฏ ๐ต๐ฉ๐ฆ ๐ค๐ข๐ณ๐ฐ๐ถ๐ด๐ฆ๐ญ.
๐ญ/ ๐๐ป๐ผ๐ ๐ฐ๐ผ๐บ๐ฝ๐น๐ฒ๐ ๐ท๐ผ๐ถ๐ป๐
LEFT JOIN, RIGHT JOIN, INNER JOIN, OUTER JOIN โ these are easy.
But SQL gets really powerful, when you know
โณ Anti Joins
โณ Self Joins
โณ Cartesian Joins
โณ Multi-Table Joins
๐ฎ/ ๐ ๐ฎ๐๐๐ฒ๐ฟ ๐ช๐ถ๐ป๐ฑ๐ผ๐ ๐ณ๐๐ป๐ฐ๐๐ถ๐ผ๐ป๐
Window functions = flexible, effective, and essential.
They give you Python-like versatility in SQL. ๐๐ถ๐ฑ๐ฆ๐ณ ๐ค๐ฐ๐ฐ๐ญ.
๐ฏ/ ๐๐ ๐ฝ๐น๐ผ๐ฟ๐ฒ ๐ฎ๐น๐๐ฒ๐ฟ๐ป๐ฎ๐๐ถ๐๐ฒ ๐๐ผ๐น๐๐๐ถ๐ผ๐ป๐
In SQL, thereโs rarely one โrightโ way to solve a problem.
By exploring alternative approaches, you develop flexibility in thinking AND learn about trade-offs.
๐ฐ/ ๐ ๐ฎ๐๐๐ฒ๐ฟ ๐พ๐๐ฒ๐ฟ๐ ๐ผ๐ฝ๐๐ถ๐บ๐ถ๐๐ฎ๐๐ถ๐ผ๐ป
Inefficient queries overload systems, cost money and waste time.
3 (super quick) tips on optimizing queries:
1. Use indexes effectively
2. Analyze execution plans
3. Reduce unnecessary operations
๐ฑ/ ๐๐ฒ๐ ๐ณ๐ฎ๐บ๐ถ๐น๐ถ๐ฎ๐ฟ ๐๐ถ๐๐ต ๐๐ง๐
ETL is the backbone of moving and preparing data.
โณ Extract: Pull data from various sources
โณ Transform: Clean, filter, and reformat the data
โณ Load: Store the cleaned data in a data warehouse
Here you can find essential SQL Interview Resources๐
https://t.iss.one/mysqldata
Like this post if you need more ๐โค๏ธ
Hope it helps :)
Here are 5 hacks to level up your SQL ๐
1. Know complex joins
2. Master Window functions
3. Explore alternative solutions
4. Master query optimization
5. Get familiar with ETL
โโโ
๐๐ต๐ธ, ๐ต๐ฉ๐ฆ๐ณ๐ฆ ๐ข๐ณ๐ฆ ๐ฑ๐ณ๐ข๐ค๐ต๐ช๐ค๐ฆ ๐ฑ๐ณ๐ฐ๐ฃ๐ญ๐ฆ๐ฎ๐ด ๐ช๐ฏ ๐ต๐ฉ๐ฆ ๐ค๐ข๐ณ๐ฐ๐ถ๐ด๐ฆ๐ญ.
๐ญ/ ๐๐ป๐ผ๐ ๐ฐ๐ผ๐บ๐ฝ๐น๐ฒ๐ ๐ท๐ผ๐ถ๐ป๐
LEFT JOIN, RIGHT JOIN, INNER JOIN, OUTER JOIN โ these are easy.
But SQL gets really powerful, when you know
โณ Anti Joins
โณ Self Joins
โณ Cartesian Joins
โณ Multi-Table Joins
๐ฎ/ ๐ ๐ฎ๐๐๐ฒ๐ฟ ๐ช๐ถ๐ป๐ฑ๐ผ๐ ๐ณ๐๐ป๐ฐ๐๐ถ๐ผ๐ป๐
Window functions = flexible, effective, and essential.
They give you Python-like versatility in SQL. ๐๐ถ๐ฑ๐ฆ๐ณ ๐ค๐ฐ๐ฐ๐ญ.
๐ฏ/ ๐๐ ๐ฝ๐น๐ผ๐ฟ๐ฒ ๐ฎ๐น๐๐ฒ๐ฟ๐ป๐ฎ๐๐ถ๐๐ฒ ๐๐ผ๐น๐๐๐ถ๐ผ๐ป๐
In SQL, thereโs rarely one โrightโ way to solve a problem.
By exploring alternative approaches, you develop flexibility in thinking AND learn about trade-offs.
๐ฐ/ ๐ ๐ฎ๐๐๐ฒ๐ฟ ๐พ๐๐ฒ๐ฟ๐ ๐ผ๐ฝ๐๐ถ๐บ๐ถ๐๐ฎ๐๐ถ๐ผ๐ป
Inefficient queries overload systems, cost money and waste time.
3 (super quick) tips on optimizing queries:
1. Use indexes effectively
2. Analyze execution plans
3. Reduce unnecessary operations
๐ฑ/ ๐๐ฒ๐ ๐ณ๐ฎ๐บ๐ถ๐น๐ถ๐ฎ๐ฟ ๐๐ถ๐๐ต ๐๐ง๐
ETL is the backbone of moving and preparing data.
โณ Extract: Pull data from various sources
โณ Transform: Clean, filter, and reformat the data
โณ Load: Store the cleaned data in a data warehouse
Here you can find essential SQL Interview Resources๐
https://t.iss.one/mysqldata
Like this post if you need more ๐โค๏ธ
Hope it helps :)
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SQL For Data Analytics
This channel covers everything you need to learn SQL for data science, data analyst, data engineer and business analyst roles.
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35 Most Common SQL Interview Questions ๐๐
1.) Explain order of execution of SQL.
2.) What is difference between where and having?
3.) What is the use of group by?
4.) Explain all types of joins in SQL?
5.) What are triggers in SQL?
6.) What is stored procedure in SQL
7.) Explain all types of window functions?
(Mainly rank, row_num, dense_rank, lead & lag)
8.) What is difference between Delete and Truncate?
9.) What is difference between DML, DDL and DCL?
10.) What are aggregate function and when do we use them? explain with few example.
11.) Which is faster between CTE and Subquery?
12.) What are constraints and types of Constraints?
13.) Types of Keys?
14.) Different types of Operators ?
15.) Difference between Group By and Where?
16.) What are Views?
17.) What are different types of constraints?
18.) What is difference between varchar and nvarchar?
19.) Similar for char and nchar?
20.) What are index and their types?
21.) What is an index? Explain its different types.
22.) List the different types of relationships in SQL.
23.) Differentiate between UNION and UNION ALL.
24.) How many types of clauses in SQL?
25.) What is the difference between UNION and UNION ALL in SQL?
26.) What are the various types of relationships in SQL?
27.) Difference between Primary Key and Secondary Key?
28.) What is the difference between where and having?
29.) Find the second highest salary of an employee?
30.) Write retention query in SQL?
31.) Write year-on-year growth in SQL?
32.) Write a query for cummulative sum in SQL?
33.) Difference between Function and Store procedure ?
34.) Do we use variable in views?
35.) What are the limitations of views?
Here you can find essential SQL Interview Resources๐
https://t.iss.one/mysqldata
Like this post if you need more ๐โค๏ธ
Hope it helps :)
1.) Explain order of execution of SQL.
2.) What is difference between where and having?
3.) What is the use of group by?
4.) Explain all types of joins in SQL?
5.) What are triggers in SQL?
6.) What is stored procedure in SQL
7.) Explain all types of window functions?
(Mainly rank, row_num, dense_rank, lead & lag)
8.) What is difference between Delete and Truncate?
9.) What is difference between DML, DDL and DCL?
10.) What are aggregate function and when do we use them? explain with few example.
11.) Which is faster between CTE and Subquery?
12.) What are constraints and types of Constraints?
13.) Types of Keys?
14.) Different types of Operators ?
15.) Difference between Group By and Where?
16.) What are Views?
17.) What are different types of constraints?
18.) What is difference between varchar and nvarchar?
19.) Similar for char and nchar?
20.) What are index and their types?
21.) What is an index? Explain its different types.
22.) List the different types of relationships in SQL.
23.) Differentiate between UNION and UNION ALL.
24.) How many types of clauses in SQL?
25.) What is the difference between UNION and UNION ALL in SQL?
26.) What are the various types of relationships in SQL?
27.) Difference between Primary Key and Secondary Key?
28.) What is the difference between where and having?
29.) Find the second highest salary of an employee?
30.) Write retention query in SQL?
31.) Write year-on-year growth in SQL?
32.) Write a query for cummulative sum in SQL?
33.) Difference between Function and Store procedure ?
34.) Do we use variable in views?
35.) What are the limitations of views?
Here you can find essential SQL Interview Resources๐
https://t.iss.one/mysqldata
Like this post if you need more ๐โค๏ธ
Hope it helps :)
๐7
SQL, or Structured Query Language, is a domain-specific language used to manage and manipulate relational databases. Here's a brief A-Z overview by @sqlanalyst
A - Aggregate Functions: Functions like COUNT, SUM, AVG, MIN, and MAX used to perform operations on data in a database.
B - BETWEEN: A SQL operator used to filter results within a specific range.
C - CREATE TABLE: SQL statement for creating a new table in a database.
D - DELETE: SQL statement used to delete records from a table.
E - EXISTS: SQL operator used in a subquery to test if a specified condition exists.
F - FOREIGN KEY: A field in a database table that is a primary key in another table, establishing a link between the two tables.
G - GROUP BY: SQL clause used to group rows that have the same values in specified columns.
H - HAVING: SQL clause used in combination with GROUP BY to filter the results.
I - INNER JOIN: SQL clause used to combine rows from two or more tables based on a related column between them.
J - JOIN: Combines rows from two or more tables based on a related column.
K - KEY: A field or set of fields in a database table that uniquely identifies each record.
L - LIKE: SQL operator used in a WHERE clause to search for a specified pattern in a column.
M - MODIFY: SQL command used to modify an existing database table.
N - NULL: Represents missing or undefined data in a database.
O - ORDER BY: SQL clause used to sort the result set in ascending or descending order.
P - PRIMARY KEY: A field in a table that uniquely identifies each record in that table.
Q - QUERY: A request for data from a database using SQL.
R - ROLLBACK: SQL command used to undo transactions that have not been saved to the database.
S - SELECT: SQL statement used to query the database and retrieve data.
T - TRUNCATE: SQL command used to delete all records from a table without logging individual row deletions.
U - UPDATE: SQL statement used to modify the existing records in a table.
V - VIEW: A virtual table based on the result of a SELECT query.
W - WHERE: SQL clause used to filter the results of a query based on a specified condition.
X - (E)XISTS: Used in conjunction with SELECT to test the existence of rows returned by a subquery.
Z - ZERO: Represents the absence of a value in numeric fields or the initial state of boolean fields.
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
A - Aggregate Functions: Functions like COUNT, SUM, AVG, MIN, and MAX used to perform operations on data in a database.
B - BETWEEN: A SQL operator used to filter results within a specific range.
C - CREATE TABLE: SQL statement for creating a new table in a database.
D - DELETE: SQL statement used to delete records from a table.
E - EXISTS: SQL operator used in a subquery to test if a specified condition exists.
F - FOREIGN KEY: A field in a database table that is a primary key in another table, establishing a link between the two tables.
G - GROUP BY: SQL clause used to group rows that have the same values in specified columns.
H - HAVING: SQL clause used in combination with GROUP BY to filter the results.
I - INNER JOIN: SQL clause used to combine rows from two or more tables based on a related column between them.
J - JOIN: Combines rows from two or more tables based on a related column.
K - KEY: A field or set of fields in a database table that uniquely identifies each record.
L - LIKE: SQL operator used in a WHERE clause to search for a specified pattern in a column.
M - MODIFY: SQL command used to modify an existing database table.
N - NULL: Represents missing or undefined data in a database.
O - ORDER BY: SQL clause used to sort the result set in ascending or descending order.
P - PRIMARY KEY: A field in a table that uniquely identifies each record in that table.
Q - QUERY: A request for data from a database using SQL.
R - ROLLBACK: SQL command used to undo transactions that have not been saved to the database.
S - SELECT: SQL statement used to query the database and retrieve data.
T - TRUNCATE: SQL command used to delete all records from a table without logging individual row deletions.
U - UPDATE: SQL statement used to modify the existing records in a table.
V - VIEW: A virtual table based on the result of a SELECT query.
W - WHERE: SQL clause used to filter the results of a query based on a specified condition.
X - (E)XISTS: Used in conjunction with SELECT to test the existence of rows returned by a subquery.
Z - ZERO: Represents the absence of a value in numeric fields or the initial state of boolean fields.
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
โค7๐5
Learn SQL: Step-by-step Guide for Beginners!
๐ 1. Start with the Basics โ SQL Commands
SQL is divided into various command categories, each with a unique purpose:
- DML (Data Manipulation Language) โ Commands like INSERT, UPDATE, and DELETE let you manage data within tables.
- DDL (Data Definition Language) โ Commands like CREATE, DROP, and ALTER define the structure of your tables and databases.
- DQL (Data Query Language) โ SELECT statements allow you to query and retrieve data from tables.
- DCL (Data Control Language) โ GRANT and REVOKE control access to your database, essential for security.
- TCL (Transaction Control Language) โ Use COMMIT, ROLLBACK, and SAVEPOINT to manage transactions effectively.
๐ 2. Essential Operators
Understanding operators is key for crafting complex queries:
- Logical Operators โ Use AND, OR, and NOT to create conditional statements.
- Comparison Operators โ =, >, <, etc., help you filter results based on specific criteria.
๐ 3. Functions for Every Need
SQL offers various functions to manipulate and analyze data:
- Numeric Functions โ Perform calculations and work with numbers.
- String Functions โ Manage text data, perfect for working with names or descriptions.
- Datetime Functions โ Handle date and time data, crucial for timelines and scheduling.
- NULL Functions โ Deal with missing or undefined values in your data.
๐ 4. Data Types
Knowing data types (e.g., Numeric, String, Datetime, Boolean, JSON) is essential for defining your tables accurately. Choose the right data type to optimize storage and performance.
๐ 5. Joins and Filtering
One of the most powerful aspects of SQL is combining data from multiple tables:
- JOIN Types โ INNER JOIN, LEFT JOIN, RIGHT JOIN, and more allow you to bring related data together based on common keys.
- Filtering โ Use WHERE, GROUP BY, HAVING, and ORDER BY clauses to refine your queries and get specific insights.
๐ผ 6. Working with Transactions
For applications where data integrity is key, learning transaction control (COMMIT, ROLLBACK) ensures consistency, especially in multi-step operations.
๐ Save this guide and keep it handy for your SQL learning journey! Whether you're just starting or looking to level up, SQL is a critical skill for anyone working with data. The more you practice, the more powerful your queries will become.
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
๐ 1. Start with the Basics โ SQL Commands
SQL is divided into various command categories, each with a unique purpose:
- DML (Data Manipulation Language) โ Commands like INSERT, UPDATE, and DELETE let you manage data within tables.
- DDL (Data Definition Language) โ Commands like CREATE, DROP, and ALTER define the structure of your tables and databases.
- DQL (Data Query Language) โ SELECT statements allow you to query and retrieve data from tables.
- DCL (Data Control Language) โ GRANT and REVOKE control access to your database, essential for security.
- TCL (Transaction Control Language) โ Use COMMIT, ROLLBACK, and SAVEPOINT to manage transactions effectively.
๐ 2. Essential Operators
Understanding operators is key for crafting complex queries:
- Logical Operators โ Use AND, OR, and NOT to create conditional statements.
- Comparison Operators โ =, >, <, etc., help you filter results based on specific criteria.
๐ 3. Functions for Every Need
SQL offers various functions to manipulate and analyze data:
- Numeric Functions โ Perform calculations and work with numbers.
- String Functions โ Manage text data, perfect for working with names or descriptions.
- Datetime Functions โ Handle date and time data, crucial for timelines and scheduling.
- NULL Functions โ Deal with missing or undefined values in your data.
๐ 4. Data Types
Knowing data types (e.g., Numeric, String, Datetime, Boolean, JSON) is essential for defining your tables accurately. Choose the right data type to optimize storage and performance.
๐ 5. Joins and Filtering
One of the most powerful aspects of SQL is combining data from multiple tables:
- JOIN Types โ INNER JOIN, LEFT JOIN, RIGHT JOIN, and more allow you to bring related data together based on common keys.
- Filtering โ Use WHERE, GROUP BY, HAVING, and ORDER BY clauses to refine your queries and get specific insights.
๐ผ 6. Working with Transactions
For applications where data integrity is key, learning transaction control (COMMIT, ROLLBACK) ensures consistency, especially in multi-step operations.
๐ Save this guide and keep it handy for your SQL learning journey! Whether you're just starting or looking to level up, SQL is a critical skill for anyone working with data. The more you practice, the more powerful your queries will become.
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
๐2โค1
SQL can be simpleโif you learn it the smart way..
If youโre aiming to become a data analyst, mastering SQL is non-negotiable.
Hereโs a smart roadmap to ace it:
1. Basics First: Understand data types, simple queries (SELECT, FROM, WHERE). Master basic filtering.
2. Joins & Relationships: Dive into INNER, LEFT, RIGHT joins. Practice combining tables to extract meaningful insights.
3. Aggregations & Functions: Get comfortable with COUNT, SUM, AVG, MAX, GROUP BY, and HAVING clauses. These are essential for summarizing data.
4. Subqueries & Nested Queries: Learn how to query within queries. This is powerful for handling complex datasets.
5. Window Functions: Explore ranking, cumulative sums, and sliding windows to work with running totals and moving averages.
6. Optimization: Study indexing and query optimization for faster, more efficient queries.
7. Real-World Scenarios: Apply your SQL knowledge to solve real-world business problems.
The journey may seem tough, but each step sharpens your skills and brings you closer to data analysis excellence. Stay consistent, practice regularly, and let SQL become your superpower! ๐ช
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
If youโre aiming to become a data analyst, mastering SQL is non-negotiable.
Hereโs a smart roadmap to ace it:
1. Basics First: Understand data types, simple queries (SELECT, FROM, WHERE). Master basic filtering.
2. Joins & Relationships: Dive into INNER, LEFT, RIGHT joins. Practice combining tables to extract meaningful insights.
3. Aggregations & Functions: Get comfortable with COUNT, SUM, AVG, MAX, GROUP BY, and HAVING clauses. These are essential for summarizing data.
4. Subqueries & Nested Queries: Learn how to query within queries. This is powerful for handling complex datasets.
5. Window Functions: Explore ranking, cumulative sums, and sliding windows to work with running totals and moving averages.
6. Optimization: Study indexing and query optimization for faster, more efficient queries.
7. Real-World Scenarios: Apply your SQL knowledge to solve real-world business problems.
The journey may seem tough, but each step sharpens your skills and brings you closer to data analysis excellence. Stay consistent, practice regularly, and let SQL become your superpower! ๐ช
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
๐3
SQL Interview Questions !!
๐ Write a query to find all employees whose salaries exceed the company's average salary.
๐ Write a query to retrieve the names of employees who work in the same department as 'John Doe'.
๐ Write a query to display the second highest salary from the Employee table without using the MAX function twice.
๐ Write a query to find all customers who have placed more than five orders.
๐ Write a query to count the total number of orders placed by each customer.
๐ Write a query to list employees who joined the company within the last 6 months.
๐ Write a query to calculate the total sales amount for each product.
๐ Write a query to list all products that have never been sold.
๐ Write a query to remove duplicate rows from a table.
๐ Write a query to identify the top 10 customers who have not placed any orders in the past year.
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
๐ Write a query to find all employees whose salaries exceed the company's average salary.
๐ Write a query to retrieve the names of employees who work in the same department as 'John Doe'.
๐ Write a query to display the second highest salary from the Employee table without using the MAX function twice.
๐ Write a query to find all customers who have placed more than five orders.
๐ Write a query to count the total number of orders placed by each customer.
๐ Write a query to list employees who joined the company within the last 6 months.
๐ Write a query to calculate the total sales amount for each product.
๐ Write a query to list all products that have never been sold.
๐ Write a query to remove duplicate rows from a table.
๐ Write a query to identify the top 10 customers who have not placed any orders in the past year.
Here you can find essential SQL Interview Resources๐
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v
Like this post if you need more ๐โค๏ธ
Hope it helps :)
๐6โค1