MySQL SELECT Statement Basics

Full clause order

SELECT   [DISTINCT] columns
FROM     table
[JOIN    other_table ON condition]
[WHERE   row_filter]
[GROUP BY columns]
[HAVING  group_filter]
[ORDER BY columns [ASC|DESC]]
[LIMIT   n OFFSET m];

Logical execution order

MySQL does not run the clauses top to bottom. It evaluates them like this:

FROM → JOIN → WHERE → GROUP BY → HAVING → SELECT → DISTINCT → ORDER BY → LIMIT

This explains two common surprises: you cannot use a SELECT alias inside WHERE (the alias does not exist yet), but you can use it in ORDER BY and HAVING.

Examples

SELECT * FROM students;                       -- everything (avoid in production code)
SELECT name_en, cgpa FROM students;           -- specific columns
SELECT DISTINCT department FROM students;     -- unique values

Aliases

SELECT
  name_en      AS student_name,
  cgpa * 25    AS percentage,
  department   dept                            -- AS is optional
FROM students AS s;

Use backticks when a name has spaces or is a reserved word: SELECT name_en AS `Full Name`.

Expressions and constants

SELECT 5 + 3, NOW(), DATABASE(), USER(), VERSION();

SELECT
  name_en,
  CONCAT(name_en, ' (', department, ')') AS label,
  ROUND(cgpa * 25, 1) AS pct
FROM students;

Limiting output

SELECT * FROM students LIMIT 5;             -- first 5
SELECT * FROM students LIMIT 10 OFFSET 20;  -- rows 21-30 (pagination)
SELECT * FROM students LIMIT 20, 10;        -- same, older syntax

LIMIT without ORDER BY gives no guaranteed order. Always pair them when paginating.

Good habits

Select only the columns you need — SELECT * transfers data you throw away and blocks covering-index optimisations.
End every statement with a semicolon.
Uppercase keywords, lowercase identifiers: it makes long queries readable.

SELECT Basics