๐ ๐ฎ๐๐๐ฒ๐ฟ ๐ฆ๐ค๐ ๐ณ๐ผ๐ฟ ๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐, ๐๐ฎ๐๐!
Here are 10 must-know SQL concepts:
โ Stored Procedure vs. Function
Procedures allow DML; functions handle calculations only.
โ Clustered vs. Non-Clustered Index
Clustered sorts data physically; non-clustered creates pointers.
โ DELETE vs. TRUNCATE
DELETE is row-specific; TRUNCATE clears all rows fast.
โ WHERE vs. HAVING
WHERE filters rows; HAVING filters after GROUP BY.
โ Primary Key vs. Unique Key
Primary is unique & non-null; Unique allows one null.
โ JOIN Types
INNER, LEFT, RIGHT, FULL JOINโcombine tables in different ways.
โ Normalization Forms
Minimizes redundancy and improves data integrity.
โ ACID Properties
Ensures reliable transactions with Atomicity, Consistency, Isolation, Durability.
โ Indexes
Speeds up data retrieval; careful use is key.
โ Subqueries
Nest queries within queries for flexible data retrieval.
Master these, and youโre SQL-interview ready!
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