Don't go any interviews without knowing this SQL queries

SQL is the backbone of data manipulation and retrieval in most applications today. Mastering SQL empowers you to interact with databases efficiently, making you a more valuable asset in any technical field. The queries you practice today will become the tools you use to solve real-world problems tomorrow.

By practicing these queries, you not only prepare yourself for interviews but also sharpen your problem-solving skills and deepen your understanding of how data is stored, processed, and retrieved.

Remember, consistency is key. The more you practice, the more patterns you’ll recognize, and the faster you’ll be able to write optimized queries. Keep challenging yourself with different scenarios, and soon, SQL will become second nature to you.

Total number of questions for each Practice test – 49

Minimum Pass percentage  – 50

Time to finish each test – 60min

Topics Covered in the Above SQL Queries

1. Basic SQL Queries

   • Selecting data from tables.

   • Filtering records using WHERE clause.

   • Ordering results with ORDER BY.

2. String Functions

   • CONCAT(), LEFT(), RIGHT(), SUBSTRING(), REPLACE(), CHARINDEX(), LEN().

   • String manipulation techniques like concatenation, substring extraction, and searching within strings.

3. Date and Time Functions

   • GETDATE(), YEAR(), MONTH(), DAY(), DATEDIFF(), DATEPART(), DATENAME().

   • Handling and manipulating dates, including calculating differences and extracting specific parts of a date.

4. Aggregate Functions

   • SUM(), AVG(), COUNT(), MAX(), MIN().

   • Performing calculations on multiple rows to return a single result.

5. JOIN Operations

   • INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN.

   • Combining rows from two or more tables based on related columns.

6. Subqueries

   • Using subqueries for complex filtering and calculations.

   • Nested queries to achieve multi-step logic.

7. Window Functions and Advanced SQL

   • Ranking and row number calculations (e.g., ROW_NUMBER(), RANK()).

   • Pagination techniques using OFFSET and FETCH.

8. Indexes and Constraints

   • Creating and managing indexes to optimize queries.

   • Adding constraints like FOREIGN KEY and ensuring referential integrity.

9. Data Modification

   • INSERT, UPDATE, DELETE.

   • Modifying data within tables, including condition-based updates and deletions.

10. Schema Changes

    • ALTER TABLE operations to modify table structures, such as adding or dropping columns.

    • Renaming columns and tables, adding constraints.

11. Null Handling

    • IS NULL, IS NOT NULL, COALESCE(), ISNULL().

    • Techniques to handle NULL values in queries and updates.

12. Conditional Logic

    • Using CASE statements for conditional logic within queries.

    • Conditional updates and selects based on different criteria.

All the best.

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