SQL data types are divided into five categories:
Character/Strings can be used to store strings like names, locations, etc. and even large text files.
Data Type | Description |
---|---|
CHAR | Maximum 8000 character long fixed length string |
VARCHAR | Maximum 8000 character long variable length string |
VARCHAR(max) | Maximum max character long variable length string |
NCHAR | Unicode Maximum 8000 character long fixed length string |
NVARCHAR | Unicode Maximum 8000 character long variable length string |
NVARCHAR(max) | Unicode Maximum max character long variable length string |
TEXT | Maximum 2GB sized variable length string |
Numeric data types can be used to store exact or decimal numeric data, from very small numbers in a bit
or tinyint
to very large numbers in a bigint
.
Data Type | Minimum | Maximum |
---|---|---|
bit | 0 | 1 |
tinyint | 0 | 255 |
smallint | -32,768 | 32,767 |
int | -2,147,483,648 | 2,147,483,647 |
bigint | -9,223,372,036,854,775,808 | 9,223,372,036,854,775,807 |
decimal | -10^38 - 1 | -10^38 - 1 |
real | -3.40E + 38 | 3.40E + 38 |
numeric | -10^38 +1 | 10^38 -1 |
float | -1.79E + 308 | 1.79E + 308 |
Date/Time data types are used to store data and time objects. Storing a date as a date/type object instead of a string can make it very easy to work with data at a later point.
Data Type | Description |
---|---|
Datetime | Date and Time stored in the YYYY-MM-DD HH:MI:SS format |
Date | Date stored in the YYYY-MM-DD format |
Time | Time stored in the HH:MI:SS format |
Timestamp | Number of seconds passed stored since ‘1970-01-01 00:00:00’ UTC |
Year | Year stored in 2-digit (from 1970-2069) or 4-digit (from 1901 2155) format |
Binary data types are used to store data in its binary form, instead of storing it as strings, which can be a big factor in saving space.
Data Type | Description |
---|---|
BINARY | Maximum length of 8000 bytes fixed binary |
VARBINARY | Maximum length of 8000 bytes variable binary |
VARBINARY(max) | Maximum length of max bytes fixed binary |
NTEXT | Maximum 2GB sized variable length binary |
These data types are for special types of data as described below:
Data Type | Description |
---|---|
CLOB | Upto 2GB large character objects |
BLOB | For storing binary large objects |
JSON | For storing JSON objects |
XML | For storing XML objects |
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