Here’s a quick cheat sheet for common data types and their storage sizes across popular relational databases (like MySQL, PostgreSQL, and SQL Server). Keep in mind that the sizes listed are typical, but some nuances or variations might apply based on specific DBMS configurations.

Numeric Data Types

Data Type	Description	Storage Size (in bytes)
TINYINT	Integer between -128 and 127 (signed)	1
SMALLINT	Integer between -32,768 and 32,767 (signed)	2
MEDIUMINT	Integer between -8,388,608 and 8,388,607	3
INT/INTEGER	Integer between -2,147,483,648 and 2,147,483,647	4
BIGINT	Large integer between -9 quintillion to +9 quintillion	8
FLOAT	Single-precision floating-point number	4
DOUBLE	Double-precision floating-point number	8
DECIMAL(p, s)	Fixed-point number (precision p, scale s)	Varies (Depends on p and s)

Character Data Types

Data Type	Description	Storage Size (in bytes)
CHAR(n)	Fixed-length string (n characters)	n
VARCHAR(n)	Variable-length string (up to n characters)	n + 1 (up to 255 bytes)
TEXT	Large variable-length string	Varies (up to 65,535 bytes)
MEDIUMTEXT	Larger variable-length string	Varies (up to 16,777,215 bytes)
LONGTEXT	Very large variable-length string	Varies (up to 4 GB)

Date and Time Data Types

Data Type	Description	Storage Size (in bytes)
DATE	Stores date in YYYY-MM-DD format	3
DATETIME	Stores date and time in YYYY-MM-DD HH:MM:SS format	8
TIMESTAMP	Stores Unix epoch timestamp	4
TIME	Stores time in HH:MM:SS format	3
YEAR	Stores a year in YYYY format	1

Binary Data Types

Data Type	Description	Storage Size (in bytes)
BINARY(n)	Fixed-length binary data	n
VARBINARY(n)	Variable-length binary data	n + 1
BLOB	Binary large object	Varies (up to 65,535 bytes)
MEDIUMBLOB	Larger binary large object	Varies (up to 16,777,215 bytes)
LONGBLOB	Very large binary large object	Varies (up to 4 GB)

Other Data Types

Data Type	Description	Storage Size (in bytes)
BOOLEAN	True or false value	1
ENUM	Enumerated list of values	1 or 2 (depending on the number of values)
SET	A set of values	1 to 8

This cheatsheet provides a general idea of storage sizes. Actual sizes may vary based on database configurations or specific implementations.