1️. Window Functions
These let you rank or number rows without losing the entire dataset. Great for things like ranking employees by salary or showing top results per group.
2️. CTEs (Common Table Expressions)
Think of these as temporary tables or “to-do lists” that make complex queries easier to read and manage.
3️.Recursive Queries
Used to work with hierarchical data like organizational charts or nested categories by processing data layer by layer.
4️. Pivoting Data
This means turning rows into columns to better summarize and visualize data in reports.
5️. COALESCE
A handy way to replace missing or null values with something meaningful, like “No Phone” instead of blank.
6️. EXISTS & NOT EXISTS
Quick ways to check if related data exists or doesn’t, without retrieving unnecessary data.
7️. CASE Statements
Add conditional logic inside queries, like “if this condition is true, then do that,” to categorize or transform data on the fly.
8️. GROUP BY + HAVING
Summarize data by groups, and filter those groups based on conditions, like departments with more than a certain number of employees.
9️. Subqueries in SELECT
Embed small queries inside bigger ones to calculate additional info per row, such as an average salary compared to each employee’s salary.
10. EXPLAIN
A tool to analyze how your query runs behind the scenes so you can spot and fix performance issues.
Mastering these concepts will make you stand out in interviews and help you work smarter with data in real life.
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