# Understanding SQL Server Data Types: Numerical and Text Date and Time

The world of SQL Server can be a complex one, with a variety of different data types that can be used to store and manipulate data. In this article, we’ll be looking at two broad categories of SQL Server data types: numerical and text.

By the end of this article, you’ll have a better understanding of these data types and when to use them.

## Numerical Data Types

The first category of SQL Server data types we’ll be looking at is numerical data types. Numerical data types are used to store numbers, and there are three primary types of numerical data types: integer, decimal, and floating-point.

### Integer Data Types

Integer data types are some of the most commonly used data types in SQL Server. The INT data type is used for integers between -2,147,483,648 and 2,147,483,647.

If you need to store larger integers, you can use the BIGINT data type, which allows for integers between -9,223,372,036,854,775,808 and 9,223,372,036,854,775,807. On the other end of the spectrum, the SMALLINT data type is used for integers between -32,768 and 32,767.

### Decimal Data Types

Decimal data types are used to store decimal numbers, which are numbers with a decimal point. The DECIMAL and NUMERIC data types are used for fixed-point numbers, which are numbers with a fixed number of decimal places.

You can specify the number of digits to the left and right of the decimal point using the precision and scale parameters. For example, DECIMAL(10,2) would allow for a total of 10 digits, with 2 digits to the right of the decimal point.

### Floating-Point Data Types

Floating-point data types are used to store numbers with a floating decimal point. The FLOAT data type is used to store single-precision floating-point numbers, which have 7 digits of precision.

If you need greater precision, you can use the REAL data type, which stores double-precision floating-point numbers with 15 digits of precision.

## Text Data Types

The second category of SQL Server data types we’ll be looking at is text data types. Text data types are used to store text and character data.

There are six primary text data types: VARCHAR, CHAR, TEXT, NVARCHAR, NCHAR, and NTEXT. The VARCHAR data type is used to store variable-length strings.

You specify the maximum length of the string when you define the column. For example, VARCHAR(50) would allow for strings of up to 50 characters in length.

The CHAR data type is used to store fixed-length strings. You specify the length of the string when you define the column. For example, CHAR(10) would create a column that can store strings of exactly 10 characters in length. The TEXT data type is used to store large amounts of text data. It can store up to 2^31-1 bytes of data, which is equivalent to 2 GB of data. However, you should be aware that the TEXT data type is being phased out in favor of the VARCHAR(MAX) data type.

The NVARCHAR data type is used to store variable-length Unicode strings. Unicode is a character encoding that can represent over 1 million characters, including character sets from all over the world. This can be very useful if you need to store text in different languages. You specify the maximum length of the string when you define the column, similar to the VARCHAR data type.

The NCHAR data type is used to store fixed-length Unicode strings. You specify the length of the string when you define the column, similar to the CHAR data type. The NTEXT data type is used to store large amounts of Unicode text data. It can store up to 2^30-1 bytes of data, which is equivalent to 1 GB of data. Similar to the TEXT data type, you should be aware that the NTEXT data type is being phased out in favor of the NVARCHAR(MAX) data type.

## Conclusion

In conclusion, SQL Server has a variety of different data types that can be used to store and manipulate data. Whether you’re working with numerical data or text data, it’s important to choose the right data type for the job.

By understanding the differences between the various data types available, you can ensure that your data is stored and manipulated in the most efficient and effective way possible.

## Date and Time Data Types

Date and time data types are an essential part of SQL Server. These data types are used to store and manipulate temporal data, including dates, times, and time intervals. In this article, we’ll discuss six primary date and time data types found in SQL Server, including the DATE, TIME, DATETIME, DATETIME2, SMALLDATETIME, and DATETIMEOFFSET data types.

### DATE Data Type

The DATE data type is used to store a date without a time component. It stores values with a precision of one day, which makes it ideal for applications that require only the date portion of a timestamp. The DATE data type can store dates between January 1, 1 AD and December 31, 9999. The format of the DATE data type is YYYY-MM-DD.

### TIME Data Type

The TIME data type is used to store a time without a date component. It stores values with a precision of one second, which makes it ideal for applications that require only the time portion of a timestamp. The TIME data type can store times between 00:00:00 and 23:59:59.9999999. The format of the TIME data type is HH:MM:SS.nnnnnnn.

### DATETIME Data Type

The DATETIME data type is used to store a date and time, with a precision of 3.33 milliseconds. It can store dates between January 1, 1753, and December 31, 9999. The format of the DATETIME data type is YYYY-MM-DD HH:MM:SS.nnn.

### DATETIME2 Data Type

The DATETIME2 data type is similar to the DATETIME data type, but it has a higher precision of up to 100 nanoseconds. It can store dates and times between January 1, 0001, and December 31, 9999. The DATETIME2 data type is the recommended data type for new developments with SQL Server 2008 and later. The format of the DATETIME2 data type is YYYY-MM-DD HH:MM:SS.nnnnnnn.

### SMALLDATETIME Data Type

The SMALLDATETIME data type is similar to the DATETIME data type but has a lower precision of one minute. It can store dates between January 1, 1900, and June 6, 2079. The format of the SMALLDATETIME data type is YYYY-MM-DD HH:MM:SS.

### DATETIMEOFFSET Data Type

The DATETIMEOFFSET data type is used to store a date and time with an offset from UTC. It is precise up to 100 nanoseconds, similar to the DATETIME2 data type. The offset is specified in minutes. The format of the DATETIMEOFFSET data type is YYYY-MM-DD HH:MM:SS.nnnnnnnHH:MM.

## Using the DATE and TIME Data Types

The DATE and TIME data types can be useful in applications that require only the date or time portion of a timestamp. For example, if you need to store appointments in a database, you can use the DATE data type to store the date of the appointment and the TIME data type to store the time of the appointment. You can then use SQL Server’s built-in functions to manipulate and calculate the data as needed.

## Using the DATETIME, SMALLDATETIME, DATETIME2, and DATETIMEOFFSET Data Types

The DATETIME, SMALLDATETIME, DATETIME2, and DATETIMEOFFSET data types are useful for applications that require the storage and manipulation of temporal information with both date and time components. You can use these data types to store timestamps for events, transactions, or other temporal information.

## Date and Time Functions

SQL Server includes a variety of built-in functions for working with date and time data types. These functions can be used to extract information from a date/time value, manipulate dates and times, and perform calculations.

### Some commonly used date and time functions include:

• GETDATE() – Returns the current system date and time.
• DATEADD() – Adds a specified number of intervals to a date/time value.
• DATEDIFF() – Returns the difference between two date/time values.
• YEAR(), MONTH(), DAY() – Returns the year, month, or day component of a date/time value.
• HOUR(), MINUTE(), SECOND() – Returns the hour, minute, or second component of a date/time value.

## Conclusion

In conclusion, SQL Server’s date and time data types are essential for storing and manipulating temporal information. From the basic DATE and TIME data types to the more complex DATETIME, SMALLDATETIME, DATETIME2, and DATETIMEOFFSET data types, there is a wide range of options available to suit different applications. By understanding these data types and the functions associated with them, you can ensure that your applications can store and manipulate time-based data effectively and efficiently.

In summary, SQL Server’s date and time data types are essential for storing and manipulating temporal information. From the basic DATE and TIME data types to the more complex DATETIME, SMALLDATETIME, DATETIME2, and DATETIMEOFFSET data types, there’s a wide range of options available to suit different applications. These data types are vital for effective and efficient storage and manipulation of time-based data.

Built-in functions like GETDATE(), DATEADD(), DATEDIFF(), YEAR(), MONTH(), and DAY() enable users to extract information from a date/time value, manipulate dates and times, and perform calculations. In conclusion, understanding these data types and functions can be an invaluable asset in building effective database systems in a variety of contexts.