For a data analytics interview, focusing on key SQL topics can be crucial. Here's a list of last-minute SQL topics to revise:
1. SQL Basics:
• SELECT statements: Syntax, SELECT DISTINCT
• WHERE clause: Conditions and operators (>, <, =, LIKE, IN, BETWEEN)
• ORDER BY clause: Sorting results
• LIMIT clause: Limiting the number of rows returned
2. Joins:
• INNER JOIN
• LEFT (OUTER) JOIN
• RIGHT (OUTER) JOIN
• FULL (OUTER) JOIN
• CROSS JOIN
• Understanding join conditions and scenarios for each type of join
3. Aggregation and Grouping:
• GROUP BY clause
• HAVING clause: Filtering grouped results
• Aggregate functions: COUNT, SUM, AVG, MIN, MAX
4. Subqueries:
• Nested subqueries: Using subqueries in SELECT, FROM, WHERE, and HAVING clauses
• Correlated subqueries
5. Common Table Expressions (CTEs):
• Syntax and use cases for CTEs (WITH clause)
6. Window Functions:
• ROW_NUMBER()
• RANK()
• DENSE_RANK()
• LEAD() and LAG()
• PARTITION BY clause
7. Data Manipulation:
• INSERT, UPDATE, DELETE statements
• Understanding transaction control with COMMIT and ROLLBACK
8. Data Definition:
• CREATE TABLE
• ALTER TABLE
• DROP TABLE
• Constraints: PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL
9. Indexing:
• Purpose and types of indexes
• How indexing affects query performance
10. Performance Optimization:
• Understanding query execution plans
• Identifying and resolving common performance issues
11. SQL Functions:
• String functions: CONCAT, SUBSTRING, LENGTH
• Date functions: DATEADD, DATEDIFF, GETDATE
• Mathematical functions: ROUND, CEILING, FLOOR
12. Stored Procedures and Triggers:
• Basics of writing and using stored procedures
• Basics of writing and using triggers
13. ETL (Extract, Transform, Load):
• Understanding the process and SQL's role in ETL operations
14. Advanced Topics (if time permits):
• Understanding complex data types (JSON, XML)
• Working with large datasets and big data considerations
Hope it helps :)
Post #2622
2.23K
- ❤ 5