SQL Server Data Types

In SQL Server, every column must have a name and a data type.
The data type defines what kind of data can be stored in that column.

SQL Server groups data types into 3 main categories:
String, Numeric, Date & Time

1. String Data Types

Used for storing text, letters, numbers, and symbols.

CHAR(n)Fixed-length text. Always uses n characters. Good for things like postal codes.

VARCHAR(n)Variable-length text. Only uses space needed. Best for names, emails, etc.

VARCHAR(MAX)For very long text (e.g. blog content).

NCHAR(n)Like CHAR, but supports Unicode (multi-language).

NVARCHAR(n)Like VARCHAR, but for Unicode.NVARCHAR(MAX)Unicode + long text.

TEXT, NTEXTOld types for long text. Don’t use — they’re deprecated.

2. Numeric Data Types

BIT0 or 1 (like True/False).TINYINTSmall number (0–255).

SMALLINTMedium-small number.

INTMost common integer (-2B to +2B).

BIGINTVery big number.

DECIMAL(p,s)Exact numbers with decimals. Best for money. (p = total digits, s = digits after decimal)

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NUMERIC(p,s)Same as DECIMAL.

FLOATDecimal with floating precision (less accurate).

REALSmaller version of FLOAT.

MONEYFor prices (4 decimal places, big range).

SMALLMONEYFor smaller prices.

3. Date & Time Data Types

Used to store dates, times, or both.

DATEOnly the date (YYYY-MM-DD).

TIMEOnly the time (hh:mm:ss).

DATETIMEDate + time. (Good default choice.)

SMALLDATETIMELess precise than DATETIME.

DATETIME2Better and more accurate version of DATETIME.

DATETIMEOFFSETLike DATETIME2, but includes time zone.

Tips

• Use VARCHAR(MAX) or NVARCHAR(MAX) for long text.
• Don’t use TEXT, NTEXT, or IMAGE — they’re outdated.
• Use BIT for yes/no or true/false.
• Use DECIMAL for anything that needs precision (like money).