DRL/DQL hota kya hai?

DRL/DQL = Data Retrieval/Query Language

Matlab: database se data nikalna (read-only).

Main command:

SELECT

1) Basic SELECT Syntax

Syntax

SELECT<columns>
FROM<table>;

Examples

SELECT name, age FROM customer;
SELECT*FROM customer;-- * = all columns

Tip: SELECT * learning ke liye ok, but production/reporting me avoid (unnecessary columns = slower + messy).

2) “Order of execution RIGHT to LEFT” — correct idea but best accurate version

Notes me “right to left” likha hai, but best way to remember logical execution order:

SQL logically executes like this:

1. FROM (which table(s) / join)
2. WHERE (row filter)
3. GROUP BY (groups)
4. HAVING (group filter)