🧩 SQL Data Types

Last Updated: January 2026

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SQL Data Types define what kind of data a column can store. They help the database:

• store data efficiently
• validate input values
• improve performance

Hinglish Tip 🗣: Data type column ka rule hota hai — kaunsa data allowed hai aur kaunsa nahi.

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🗂️ Main Categories of SQL Data Types

Category	Purpose
Numeric	Store numbers
Character / String	Store text values
Date & Time	Store date and time
Boolean	Store true / false values
Binary	Store binary data
Special	Store JSON,UUIDs,etc

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🔢 Numeric Data Types

Used to store numbers.

Data Type	Description	Range	Example
INT / INTEGER	Whole numbers	-2147483648 to 2147483647	10, -5
SMALLINT	Smaller range integers	-32768 to 32767	32000
TINYINT	Very small integers	0 to 255	124
BIGINT	Very large integers	-9223372036854775808 to 9223372036854775807	9000
DECIMAL(p,s)	Exact decimal values	Custom range	DECIMAL(5,2)
FLOAT / DOUBLE	Approximate decimal values	-3.4E+38 to 1.7E+38	98.76

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🔤 Character / String Data Types

Used to store text.

Data Type	Description	Example
CHAR(n)	Fixed-length string	CHAR(5) → 'Amit '
VARCHAR(n)	Variable-length string	VARCHAR(20) → 'Rahul'
TEXT	Large text data	Description, comments
NVARCHAR(n)	Unicode variable-length string (Hindi)	NVARCHAR(20) → 'राहुल'
NCHAR(n)	Unicode fixed-length string (Hindi)	NCHAR(5) → 'राहुल'
LONGTEXT	Large text data (Unicode)	Description, comments

Hinglish Tip 🗣: > CHAR fixed size leta hai, VARCHAR sirf jitna text ho utna hi space use karta hai.

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📅 Date & Time Data Types

Used to store dates and time values.

Data Type	Description	Range	Example
DATE(YYYY-MM-DD)	Stores date	1000-01-01 to 9999-12-31	2026-01-07
TIME(HH:MM:SS)	Stores time	00:00:00 to 23:59:59	14:30:00
DATETIME(YYYY-MM-DD HH:MM:SS)	Date and time	1000-01-01 00:00:00 to 9999-12-31 23:59:59	2026-01-07 14:30
TIMESTAMP(YYYY-MM-DD HH:MM:SS)	Auto-updated date & time according to zone	1970-01-01 00:00:01 to 2038-01-19 23:59:59 UTC	System generated
YEAR	Stores year	1901 to 2155	2026
CURRENT_DATE	Current date	System generated	System generated
CURRENT_TIME	Current time	System generated	System generated
CURRENT_TIMESTAMP/NOW	Current date & time	System generated	System generated

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✅ Boolean Data Type

Used to store true or false values.

Data Type	Description	Stored As
BOOLEAN / BOOL	Logical true or false	TRUE / FALSE
BIT	Binary 1 or 0	0 / 1

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Binary Data Types

Used to store binary data like images, files, etc.

Data Type	Description	Stored As
BLOB	Binary large object	Binary data file,image etc
BINARY	Fixed-length binary data	Binary data

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Special Data Types

Data Type	Description	Example
ENUM	Stores a set of possible values	Enum('red', 'green', 'blue')
GEOMETRY	Stores geometric data	POINT(1 2)
JSON	Stores key value data	{"name": "Rahul"}
XML	Stores Markup data	<h1>Rahul</h1>
UUID	Stores unique identifier	UUID()

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