SQL Data Types

SQL data types define the kind of value a column can hold. Choosing the correct data type is essential for database performance, accuracy, and storage efficiency.

Each SQL database system (MySQL, SQL Server, MS Access, etc.) supports different data types. Always refer to your database documentation for compatibility. In our SQL playground, some data types and advanced features may not be supported, especially those that are platform-specific. If a feature is not supported in our playground, you may see a syntax error.

SQL Data Types MySQL Data Types (Version 8.0)

In MySQL, data types fall into three broad categories: String, Numeric, and Date/Time.

String Data Types

Data Type	Description
CHAR(size)	Fixed-length string (0–255).
VARCHAR(size)	Variable-length string (0–65,535).
TEXT	Holds up to 65,535 characters.
TINYTEXT	Up to 255 characters.
BLOB	Binary Large Object (up to 65,535 bytes).
ENUM(val1,...)	One value from a list.
SET(val1,...)	Zero or more values from a list.

Note: In our SQL playground, only VARCHAR, CHAR, and TEXT types are reliably supported.

Numeric Data Types

Data Type	Description
TINYINT	Very small integer (-128 to 127).
SMALLINT	Small integer.
INT/INTEGER	Standard integer (-2B to 2B).
BIGINT	Large integer.
FLOAT(p)	Approximate floating point.
DOUBLE	Double-precision float.
DECIMAL(p,s)	Fixed-point number.
BOOL/BOOLEAN	Alias for TINYINT(1) (0 = false, 1 = true).

Note: These are commonly supported in our playground.

Date and Time Data Types

Data Type	Description
DATE	‘YYYY-MM-DD’.
DATETIME	‘YYYY-MM-DD hh:mm:ss’.
TIMESTAMP	Unix epoch-based time.
TIME	Time only.
YEAR	Four-digit year.

Note: DATE, DATETIME, and TIME are supported in our playground. TIMESTAMP might behave differently.

SQL Data Types SQL Server Data Types

SQL Server uses slightly different data types and naming conventions.

String Data Types

Data Type	Description
CHAR(n)	Fixed-length, non-Unicode.
VARCHAR(n)	Variable-length, non-Unicode.
NCHAR(n)	Fixed-length Unicode.
NVARCHAR(n)	Variable-length Unicode.

Important: SQL Server–specific types like NVARCHAR are not available in our playground.

Numeric Data Types

Data Type	Description
BIT	0 or 1.
TINYINT	0 to 255.
SMALLINT	Small integer.
INT	Standard integer.
BIGINT	Large integer.
DECIMAL(p,s)	Exact decimal.
FLOAT, REAL	Approximate decimals.

Note: INT, FLOAT, DECIMAL, and BIT are supported in the playground.

Date and Time Data Types

Data Type	Description
DATE	Date only.
DATETIME	Date and time.
SMALLDATETIME	Less precision.
TIME	Time only.

Note: Precision might vary. Use DATE, DATETIME, and TIME in the playground.

Other Data Types

Data Type	Description
UNIQUEIDENTIFIER	GUID
XML	XML formatted data
SQL_VARIANT	Stores various types
TABLE, CURSOR	Advanced types

Important: Not supported in our playground.

SQL Data Types MS Access Data Types

MS Access uses simpler data types suitable for desktop applications.

Data Type	Description
Text	Up to 255 characters.
Memo	Long text (up to 65,536 chars).
Byte	0 to 255.
Integer	-32,768 to 32,767.
Long	-2B to 2B.
Single, Double	Floating point numbers.
Currency	Decimal values for money.
AutoNumber	Auto-increment field.
Date/Time	Stores both date and time.
Yes/No	Boolean.
OLE Object, Hyperlink, Lookup Wizard	Multimedia or UI fields.

Note: MS Access-specific features like AutoNumber or OLE Object are not supported in our playground.

SQL Data Types Labs